Pick your seat in advance depending on what's important to you.

Try to fly first class if you can swing it with your new job. Or at least better than economy.

Take your own bottle of water onto the plane. You have to buy it at the gate though. You still can probably take a lunch pack with food.

Bring or buy a book. Most people (me too) don't have much time to read.

Travel very light. Less bags and things to haul all around.

Wear comfy clothes, like a cotton tracksuit. Do bring a hoodie, airplanes can be cold.