A few years ago I have had the experience of being a flight attendant for El-Al Israeli Airlines. It was a great experience that had taught me much about life and the human (and especially Israeli) nature, and one of the most important things I had learnt was how to manage your flight as a passenger and make it as convenient as you can. Following are some tips I believe can make a more comfortable flight:

1. Head start - Make sure to be one of the first passengers to check into the flight, this way you can have better seats to chose from.
2. Choosing a seat - I think that unless you are suffering from prostate problems the window seats are the best you can get. The front rows of the airplane have much less turbulence than the rear ones.
3. Carry on Luggage - Make your carry on luggage as small as you can, but be sure to pack one set of underwear, a couple of books, a pen (for those landing forms) and a toothbrush.
4. Toilet - the best times to visit the toilet is right after take-off, and between meals.
5. Drinking - Drink as much water as you can. It will make you use the toilets more often and make more walks as well as prevent you from dehydrating.
6. Alcohol -Although some airlines serve free alcohol, it is not recommended to drink any alcohol during the flight since the airplane air is thin and dry, if you add some alcohol to that you