1) If you're a keener and get on the plane first then I suggest you tuck your behind in from the aisle, wait for the hoards to go by and then organize your in-flight nest of magazines, bottled water and snacks. Don't hold up the line just because you can't decide between a trashy magazine or reading your copy of Emily's Seams...just pick Emily's Seams.
2) Shower before getting on a plane and wear clean clothes. Having to sit in a metal tube is horrible enough. Having to do it while sitting beside someone that smells like gym socks is just plain and simply nasty.
3) Screaming child? Don't stare, shoot the parents dirty looks or mutter "why don't they shut that kid up?". Short of a blow to the head or a shot of something from the in-flight service booze cart, the parents don't have too many options.
4) If you have a sensitive stomach, think about starving yourself on the plane. Sick people on a plane is like yawning. You see someone do it and you just can't help but want to vomit yourself.
5) By all means, tip that seat back but do it slowly and be mindful of when the last drink cart whizzed by. Nobody likes a lap full of rye and ginger because you just had to be titled back 20 degrees right frigging now!
Now sit back, seats and tray tables in their upright and locked positions and try to forget that you are challenging the force of gravity.