I find that reading, or movies completely relax me because it takes my mind away from thinking about bad things that might happen, which are not in my control.
Maybe a puzzle, sudoku, cross word?
what is something you enjoy most? Find that out, and carry it with you.
get a better boarding position, pay if you have to. settle down, relax, stay hydrated, get some noise cancelling headphones.
if watching out the window makes it worse, dont do it. focus on whatever activity you picked up.
if a turbulence happens, my thinking goes like this - "if this were a bus or a car, would this level of turbulence make me worried?", the answer is always No. if it gets worse, allow yourself to be scared. dont hold it back, say it out loud to your neighbor or to yourself --- "ooh, that was rough. " verbalizing our fears help us stay less panicked.
hope my tips help you.
travel safe and enjoy the wide open skies