Go out of your way to be nice to other people on the plane
I’m not saying you have to share your life story with the person sitting next to you, but at least say hello. Introduce yourself. Be pleasant. This will make it much less awkward when you have to ask them to get up from their seat for the 100th time so you can go to the bathroom or do yoga in the aisle. And when it comes to the crew, remember these are the people who have the power to do you favors that will make you more comfortable. Say thank you when they offer you that hot towel, even if you don’t know what the hell to do with it. They also know where those cute little bottles of booze are hidden, and if the plane is going down, it’s probably best to be on their good side.
Wear comfortable clothes
Unless you’re Beyonce there is absolutely no reason to fly in 6in heels and leather pants. You’re going to be sitting for a very long time so you might as well get comfortable. If you don’t want to be seen in public wearing your Thanksgiving stretchy pants then pack them in your carry-on and change in the bathroom once the cabin lights are dimmed. Due to things like cabin pressure, lack of mobility, dehydration, and consuming excessive amounts of sodium via the 15 packs of peanuts you ate out of boredom, your legs and feet will tend to swell. Wearing shoes with loose laces gives your feet a little room to expand. As long as your feet don’t stink up the entire cabin you could always make yourself at home and ditch your shoes completely, which is one tip that made my flight so much more bearable. Just make sure you put your shoes back on before you visit the bathroom because, ew.