My tips for solo travelling domestic flights:
Know what you're
allowed to take on board.
Take proper photo id.
Arrive 1 hr 45 (EDI) or 2 hrs (LTN) before departure. The objective is to get to the gate 30 minutes before departure.
Relax in the check in queue, and in the security queue.
Put your phone and your money in your coat, and put your coat and shoes on the security belt before they have to ask. Being searched and having arguments with security causes stress.
Buy a bottle of water and then go straight to the gate and read.
Get on after the main rush, you'll still get a seat, and you can choose (to some extent) who you sit next to.
Listen to and watch the safety briefing. It prevents you from getting offloaded.
Optionally chat to the person next to you during the flight. It's not the underground, and people do talk. A one hour flight can seem like 10 minutes.
As soon as you start descent, drink your water over a 10 minute period. It helps your ears clear, and beats the dehydration that can make you feel tired and grumpy.
On arrival wait in your seat for all the fools to stand up, get their bags and have to keep standing, crushed.
Walk off, calm and relaxed.
Tip the pilot.