While I'm usually firmly ensconced in the best seat in the house, which is the furthest forward left seat, I've occaisionally had to inhabit a seat in the cattle section. On those occasions, I always select a seat as far aft as I can. Depending on the aicraft make and model, the aft seats are quieter and, most importantly, closer to the all important galley area. Although I'm familiar with most of the cabin crews (being a pilot) even the
tourista can make friends with them through friendly banter and acquire some extra goodies. Often, there are left over, unopened, of course, meals that someone didn't want or soft drinks and the all important water bottles. (Airplane humidity is less that 20%).
I've friends that travel extensively and they say one of their best investments is in a device like this:
http://www.archos.com/products/gen_5/archos_60 5wifi/index.html?country=global&lang=en ... Watch some of those old movies you always said you wanted to review.
As
jno and others have suggested, walk as much and as often as possible. Be sure to secure an aisle seat!
Best of luck...