Getting there

Before you get there, you should check where "there" is.

Getting around huge venues with little to none, or abundant but conflicting information can be intimidating and time consuming. On the other hand, it can be simple with just a little well thought out planning and preparation. 
Open your favourite navigation app and check how far and how long it will take for you to reach your airport. Hint – checking an ETA at 10:17 will most definitely not reflect rush hour drama if your actual flight is at 16:45. Official websites for major airports will clearly state how early you should arrive at the airport, and you need to make sure to add your commute time to this official estimate. International versus local flights estimate makes a difference at international airports, but local ones usually have only a few check-in counters and even fewer security points, meaning you should lean towards the international estimates. Butter zone – at least two hours before boarding, aiming at three.

Being there

You'd think that the first thing you need to do at an airport is to check-in, but you'd be gravely mistaken. You should actually check-in online, 48 to 23 hours prior to your departure, on the airline's web or by using the mobile app. There are several reasons for this so let's go through them:

1. Time
   You can spend it doing almost anything else, and it would definitely be better spent than standing in line with other people in endless queues, waiting to negotiate your seating with the apathetic counter employee. Basically, once your ticket is booked, go to the respective airline's web or mobile app and review your booking. Apart from inputting your contact and travel details, you can check how early they allow online check-in and mark your calendar to do so. Which brings us to point #2.
2. Convenience
   Checking-in early gives you the convenience of actually picking your seat, while there are still some vacancies. Depending on your travel preferences* you might opt-in for a front or back seat, aisle or window. Additionally, an early check-in will guarantee some added security in the very likely event of overbooking.
   *Middle seats, if there are seat rows of three, are a gateway to hell and unless you know you're going to be trapped between Chrises (Evans and Hemsworth), never ever select this seat.
3. Overbooking
   Airlines apparently cannot count and are very pragmatic when it comes to making extra money off of that deficit. They will typically oversell the tickets for any given flight, expecting that, statistically, someone will not make it. If you check-in early and have your seat selected, you will be further down the line of involuntary volunteers that will have to forfeit that particular flight for a later one, due to said overbooking.
4. Stress
   Travel generates copious amounts of stress, and running into problems will just have more of it pile on. Not knowing where and if you will be able to sit on your plane ride is stressful. Being in a group or travelling as a family, and then being separated from your loved ones is not the least bit fun.

If you're still not convinced to check-in online and at your earliest convenience, you knowingly accept the probability of any one of the issues mentioned above. Meaning you will need to wiggle your way to the counter and negotiate your way into a hopefully half decent seat, before finally dropping off your luggage. Which brings us to the next big decision; carry on or checked luggage?

Luggage

The sheer volume of luggage you are taking with you will depend on several factors, like:

• how many days are you staying for?
• what is the weather like at your destination (during the trip, not in general)?
• are you relentlessly indecisive when it comes to fashion combinations
• how tightly can you pack stuff?
• do you have checked luggage in your fare?
• are you willing to cash out for checked luggage (usually 100 EUR or USD per round trip per checked bag, depending on airline)?
• will you be buying stuff during your stay (mugs, magnets, shoes, shirts, random-crap-of-your-liking-and-big-volume, gifts for )?

Before we get to suggestions, let's address the standards. They depend on the airline.
If you like numbers, feel free to review lots of them here. Some airlines are hell-bent on dimensions (each dimension or some weird average of all of them or their sum), some on weight, and many on both. This means that once you get to your gate, and if the flight is (almost) fully booked, there will be an announcement that they will be more than glad to check your carry on luggage for free. There have been instances when this info was shared during luggage drop off or airport check-in, but do not count on this happening as a rule. If they offer this, feel free to hand yours in, but only after your have:

• taken out everything you might need on your person during and after the flight (like medicine, a sweater, documents)
• secured everything fragile in the bag (gentle is not something that your bag will experience in any transit)
• locked the bag (and scrambled the lock)

Now, if they want to check your bag in, and you really do not want them to, you will most likely need to enter a vigorous discussion with the gate crew. They will make you try to fit your bag into their plastic or cardboard frame to see if it exceeds 55x40x23 cm / 22x16x9 in. (to prove you cannot take it with you), or they will weigh it to see if it exceeds 8 kg (22 lb) (to prove you cannot take it with you), or they will throw arguments like full flight and not enough room, which should be translated to "our math sucks and we know that people will scramble to get their bags in (any overhead compartment), resulting in a potential delay in boarding which is a nuisance". It is entirely your choice whether to push this or not. If you really want your bag with you, a statement like "I have fragile contents in my bag and I insist on taking it with me, unless you can guarantee compensation for any and all damages caused by manhandling" should be enough. Damages and compensation are great deterrent keywords to make the gate staff leave you alone. No guarantees that they won't smell fear and lack of resolve on you and get that bag anyway.

How do you pick which bag to take? For convenience, I will list the most common combinations, depending on most common trip types and how to plan for them.

Reference guide

Checked luggage: dimensions vary, I have seen some really crazy stuff. Limit is 23 kg (50 lb). Anything more than that and you will be charged extra money.
Carry on luggage: dimensions 55x40x23 cm (22x16x9 in). Limit is 8 kg (22 lb). Anything more than that and you will be charged extra money, and most likely have to surrender your luggage to be checked in.
Personal item: usually a backpack. Do not abuse the occasional lack of specification for this item. This is for your laptop, iPad and any other gadget of similar size and purpose, that the TSA will ask you to take out and submit for inspection in those plastic bins.

Short trip (up to and including three days)

In general you should be fairly OK with one carry on and a personal item. If it is warm, this is truly a no-brainer. If it is cold, it can still be managed, just keep in mind that the bulkiest things need to be on you during the flight (jacket, boots, etc).

Longer trip (four to seven days)

If it is warm, you can still pull this off with just a carry on and a personal item. Otherwise you will need either two carry on sized bags, or one large one to be checked, or a combination of both. You will still be stuck with your personal item, because batteries and convenience (gadgets, medicine, wallet, etc). But how do you choose between two small bags and one big bag?

Small digression;
Bags can get lost. If you are travelling and intend to participate in a business meeting or to speak/attend a conference, you might want to be absolutely sure that you won't need to buy new clothes 30 minutes before the event. The only way to be sure is to actually have a backup set of clothes with you at all times. Tedious, but reassuring. This is the main reason why I would always suggest on having a carry on, in addition to checked luggage (regardless of its size) instead of just checked luggage.

Long trip (over one week)

You are pretty much stuck with the big checked bag. Again, depending on your preferences you will need to decide whether a personal item is enough, or you need an additional carry-on, but for longer trips the biggest part of packing is related to clothes, and it might be simpler to wash them at your destination than pack too much.

In the end it boils down to whether you value your comfort (checked luggage with most likely find its way to your destination with little help from you) or your peace of mind (I believe this is more valuable).

Security

The single most intrusive part of the beginning of your journey. Definitely the most painful one if you are not careful.
The job of the security personnel is to check whether or not you and your carry on items are a danger to other travellers and the crew (basically everyone). Not every security check is the same, however, and sometimes the personnel in front and after the screening might not be on the same mental regulatory frequency.  

There are some items that consistently cause mayhem, like belts, bras, items in pockets, scarves, bracelets, necklaces, watches, jackets, hoodies, sweaters, bottles of water (empty bottle is OK), but above all attempt at humour. Shoes are a wild card. Some airports aggressively insist you take them off, while some are irritated when you do. It is also very controversial where you decide to put them, in a plastic bin or directly on the conveyor belt. You should listen to the officer repeating the manual as you approach the conveyor belt, but it does not hurt to ask them about the shoes and where to place them - but why take the off if you need not to?

You will need to put all your belongings in plastic bins, but somewhat unevenly distributed. Word of caution, never ever place things like clothes and belts outside the bins, because they can get lodged in there. Most common distribution per bin, and in the optimal order (meaning the officers will not touch your stuff or rearrange everything):

• First you place your personal item (backpack), after having removed any larger electronic gadgets and all the liquids from it. This does not apply to your smartphone(s). Leave those safely tucked away in your backpack. You should also leave your passport, watch, jewellery and pocket contents in your backpack. 
• Second bin is reserved for the bigger electronic gadgets – laptops and tablets. If you have only one item here, you can place your 1l transparent plastic ziplock bag, containing liquids, each 100 ml max. Do not exceed this, as it will end up in the trash can.
• Third bin is reserved for the liquids (if you did not have room for them in the second one) and all of the clothes you needed to take off before the screening. 
• Fourth bin might contain your carry on bag, or it may not – as it can go on the conveyor belt directly. Depends on the personnel, ask them. If you do leave any of the bigger electronics or liquids in there, prepare for drama, unpacking, rearranging, loss of items (as they might get thrown out), repacking and stress. Don't be the person that leaves stuff in the carry on that should not be there.

Why did you need to arrange your things in this order? Well, the answer is practicality and speed. Having your backpack in first, you will have it and all your critical belongings with you (passport, boarding passes, smartphone, etc) as soon as you are on the other side. You are then free to pack your gadgets and liquids in when they come in second and/or third. Put your clothes on as well. Next comes your bag, that can be taken off the belt easily (because you did a good job making sure there is nothing problematic inside). Shoes, like I mentioned, are a wild card. If you had to take them off, make sure they come last – this is OK because it is more important to first focus on the valuables which might get "misplaced", than smelly shoes that nobody wants to touch. If they are on you, one annoying step less!

Now, in the likely event you get chosen for additional screening, be prepared for a drug/explosives swipe at best and some unnecessary touching at worst. The most common items that will cause the touching are bras (due to metal underwires) and belts (due to the metal buckle). You can avoid the belt drama, so be mindful of that before going through for screening. 

I mentioned that humour might be an issue. Do this at your own peril. Generally speaking, those officers interact with hundreds of people and repeat the rules all the time (sometimes twice to the same person), so give them a break. At best they will politely nod and smile, at worst you will get a cavity search because you seemed "weird and incoherent". 

Post security

Congratulations, you made it! You can frolic in the never-ending labyrinth of duty free shops and overpriced restaurants on your way to your gate. Don't buy things you don't need. But if you need something, buy it only you have room in your personal item or carry on. You can also fill that empty bottle with water at any fountain now, as you will be thirsty at some point.

At this point the most important thing is to identify your gate and the general direction it is in. Depending from airport to airport, you could need anywhere from five to 50+ minutes to get to it. Locate the nearest departures display screen and check whether your gate has been announced – but keep in mind that it can be changed up until boarding, so be diligent and recheck every once in a while. If you have an hour or more to boarding, feel free to grab a drink or meal somewhere (preferably near your gate or departures display screen) and relax. If your boarding should start within a half an hour (it will be clearly displayed everywhere, like your boarding pass, all the screens, mobile app, etc) go to your gate and sit down. 

At the gate

Once you have positioned yourself comfortably at your gate, feel free to relax, read, post insta-worthy pictures of aircraft on social media and whatever else that floats your boat. But don't stand. You should stand up when they announce that boarding has begun. You have no way of knowing which crazy algorithm they will use to board you – but they will certainly board the priority travellers first (all those ruby, gold, platinum, emerald, pink, magenta, unicorn sects and cults, those in need of assistance and families with small children). Once those are in (the hall/stairs/escalator/bridge), they will start with the rest. It might be by rows (front to back or vice versa), it might be by the fare type, but you standing too early and too eagerly will not speed any of this up. Once it's your time, have your passport and boarding pass ready. You will either pass through the counter yourself – by swiping your boarding pass on the scanner, or the staff at the counter will do that for you, simultaneously checking you passport. 

Once you've passed this point, it is only a matter of getting to your seat (check which seat that is), after which your "On the plane" adventure can begin.

Happy travels!