I think looking fashionable for guys is pretty easy.Just stick to the classics, don't try too hard to be stylish. Don't try to dress like Justin Timberlake because you're not him and he would look stupid if he was any other guy wearing exactly what he wears. For jeans, bootcut, straight, relaxed etc are all fine, make sure they fit decently, not too baggy and you are in the clear. Don't buy skinny jeans, they look stupid and are for emo queers.For pants, khahki pants without pleats are always good. Don't wear cargo pants unless you are doing a military mission, hiking or yardwork.For shirts, polos are fine, just have nothing to in your design. Button ups are good, I usually keep any patterns or stripes minimal and like solid colors. Don't want to wear a white and red vertical striped shirt and look like a barbershop pole. For t-shirts, usually the less complicated the better. Steer clear of Ed Hardy, Affliction or Tapout shirts, if you don't want to look like a tool. A simple polo t-shirt with the horse on it is usually pretty good. If you want designs, make sure they aren't obnoxious. Don't wear an American Eagle or Old Navy Graphic T that says Bronx, NY Intramural Boxing Champion or anything like that.Finally shoes, for casual shoes, just have a pair of normal sneakers for athletic needs and comfortability and if I want to be casual without being dressy, I have a pair of Sperrys which go good with anything from jeans to khakis to shorts.I am not the don of fashion or anything and don't try to be. I have worked in clothing stores so I have a decent understanding of style and think these are some of the ways to look pretty good without trying dress like one of the dudes of Project Runway or something.