try to cut down on carbs, those things turn into sugar which if not burned off will turn into fat. like chips and whatnot.
and like mike said, cut out all fast food, high-sugar sodas, that diet shit, only helps some, or get the sugar-free stuff. and eating late.
try and come up with a work out plan you could easily do about 2-3 times a week, like tae-bo or some shit like that. (my girlfriend was telling me about some belly dancing shit on TV she does, lol, i'll find out what it is if you want)
i don't know if you got a girl/wife/kids or not, but if you do, then get em to go walking with you around the block a couple times, its what i did, and maybe on the weekends or something, go play some type of active sport, like basketball/football/soccer somethign that will get you moving and your blood flowing.

oh and if you smoke.....quit!
i doubt you do though, but i'd throw it up anyway.