1) You will be in close quarters with strangers for a considerable period of time. Therefore, please ensure you wash and use deodorant. However avoid overuse of heavily perfumed items, these can be migraine triggers/allergic reactors for many people.
2) Armrests: The aisle and window seats have 2 armrests. Therefore it is polite to leave the inner armrest for the person sandwiched in between the aisle and window, in order to make the journey as comfortable as possible for everyone, and not just yourself. Also, the armrests are there for a reason, and putting them up is not only an intrusion into your seatmates space, but can also be dangerous.
3) Children: It is your job to ensure your children are kept quietly entertained throughout the flight. Do not provide noisy games and toys for them unless you can also provide headphones to keep the noise private. Do not allow your children to run along the aisles of the plane, as this can be both disruptionary to your fellow passengers, and dangerous. Do not allow your children to constantly badger the people sitting in front or behind you. While I am sure they are entertaining, I do not need 60 mins of proof of this fact.
4) Space: This is very limited on a plane. However please try to manouver yourself while causing as little disruption as possible to your seatmates in front of you. Being kicked and kneed in the back every 5 mins is no-ones idea of a fun flight.
5) Babies: It is not acceptable to change your baby on the plane seat. The only acceptable place to change your baby is in the toilet, on the change table provided, or else on a mat on the toilet floor. If it is not possible to do this due to space/health limitations, see a flight attendant, and they will be able to find you an alternative that will provide minimum disruption to all concerned. Please also do your best to keep your baby quiet. I know this is not always possible, however your fellow passengers will look a lot better upon you if they can see you at least attempting to quiet a screaming baby, rather than just ignoring it.
6) Storage bins: Please use the bins directly above your seat. Taking ones further back/forward just inconveniences everyone, including yourself. Also make sure anything you may need during the flight is close at hand. Your fellow passengers do not want to be made to move every 10 mins while you grab your handcream/reading glasses/water etc.
7) Personal Space: If your seatmate is reading/listening to music/knitting etc. it means they do not wish to be disturbed.

Sleeping: If you wish to sleep on the flight, please do not recline your chair all the way back. As already stated, space is limited on these flights, and a few extra inches for yourself, means less inches for the passenger behind you.
9) Dis-embarking: It is not a race to the terminal. If you do not have a connecting flight, then let those who do leave first. Once you get off the plane, you are still going to have to wait for your luggage to arrive, so rushing is not going to make you get out any faster.
10) Luggage collection: Do not crowd the carousel. Doing so prevents other people from seeing their luggage. Stand back until you see your case on the carousel, standing right beside the carousel will not make your luggage arrive any faster! On this note, please keep children away from the carousel. It is not safe.
11) Security: Please make sure you are prepared when you go to security. Your fellow travellers do not want to wait 20 mins while you finally remember to empty your pockets, and pack away everything into your carry on. Before approaching security pack everything into your carry on and have your coat on your arm ready to put into a bin. On this note please dress to make security as simple as possible. This is not the time to try out those new boots with the laces up to the knees, or layer 4 different tops and cardigans.
12) When moving through the airport, please keep moving in the narrow corridors and on the walkways. If you need to stop move to one side first, and avoid blocking other passengers. Also please keep to the right on the moving walkways, if you do not wish to walk.