I used to be a seasoned traveller (dh not so much ). Not now. I'm a total novice flying long haul with dd and dh. It'll be her first visit to the US and her first flight ever. DH is a bit nervous but has total faith in me. 
Tell me about online check in, liquid restrictions in flight, api, charging up electronic devices before going. US customs.
Assume I know nothing.
While you're at it, tell me about anything you take to make the flight more comfy.
I was used to roughing it. I have MS now (not too troubling yet but I can't rough it the way I used to).
Many thanks 