Pack your bags wisely. Your liquids should be in containers no bigger than 100ml and they all should be in a clear plastic bag. One per person max. Don't forget this includes things like lipstick. Put these near the top of your bag in an easy to get to place. Ditto all your cables and electronics. If you have a lightweight canvas bag or plastic bag I recommend sticking all your electronics in one BEFORE you go to the airport. That way you can just tip it out rather than scrabbling around for them.
I also recommend taking an empty water bottle.
You confirm your seat online when it becomes available (usually a few days before).
LEAVE EARLY. It is better to be bored at the airport than panicking through security and legging it to your gate.
Check your bags in on arrival.
Then go through to security. You will need your boarding pass but not your passport.
When you get to the conveyor belt get out your two nicely packed bags - one for liquids and one for electronics (and quietly chuckle at the hen do next to you having a meltdown because they can't find their hair dryer and security are binning half their make up). You may need to take your shoes off. Make sure your pockets are empty and you remove coats and belts. Stick them all in the tray. Remember you can take your time putting everything back in your bag once you get through security.
Once you are through you should have some time to chill. You can fill your empty water bottle at the drinking fountain (usually located by the toilets). This means you don't get fleeced for water in the airport or on the plane. I find it makes a huge difference as I get very dehydrated flying - it also means I have a drink when I arrive / stay at a hotel.
Keep an eye on the screens for your gate number. It will tell you to wait in lounge and usually gives a time until the gate number. You will not be called to the gate. You need to pay attention to the screens to know where to go.
Don't get too drunk you fail to pay attention to the screens.
Wait by the gate until they call the flight. There is no rush to board as you have your seats allocated. You will need to show your passport and boarding pass.
Check your seat numbers - your boarding pass may show front or rear in reference to the door of the plane you should use. Get on the plane.
Relax. Switch off your mobile (or put it on airplane mode). Enjoy the next couple of hours in a wobbly tin can with people programmed to annoy you.