On long-hauls, I like to bring traditional books or magazines along with tablet/phone. At some point, I like to take a break from electronics.

Drink lots of water.

For the electronics, bring plenty of juice. If your device doesn't have a swappable battery, then bring one or two of those portable external battery packs. I have a 12000 mAh one that can juice a tablet and a phone at the same time. Cost $25 at Amazon.

I have a Samsung Galaxy S3, so I also have a few extra batteries in my backpack. ($3 knockoffs, not as good as the OEM battery but good enough.)

Your seat may or may not have a power source. If it does, it may or may not work. (About a 50-50 shot IME.)

Drink lots of water.

I'm an aisle guy because I like to be able to get up whenever I want. But some people are window people and that's okay too. When I am at the window, I tend to get up whenever Mr. Aisle gets up whether I think I need it or not. Figure it's good to move around on occasion, even if I don't use the toilet.

I don't bother with drugs. Well, other than wine...

Turbulence has never really bothered me. People talk about it on FT, it happens once in a while, but I've thankfully never had to endure truly horrific turbulence. Most people haven't, and you probably won't.

Drink lots of water.

Pack light.

Be nice to the FA's. They'll be nice to you. (Most of them, anyway.)

Did I mention the water?