I like a guy who keeps it simple. Jeans almost always looks amazing on a guy, unless we're talking about guys squeezing into skinny jeans who don't have the body for it or bizarre colors. I appreciate a guy with a good sense of humor so I think its' cute when I see guys wearing funny cartoon or graphic t shirts around. Not rude or anything. Just something funny-ish. Hoodies also look super comfy and nice, especially if they fit well and aren't too baggy. In winter, I must say a guy wearing a scarf looks super attractive to me as well. But I know it's summer over there in the USA. I also really like the look of plaid shirts on guys. It's very hot. A nice plaid shirt with a dark colored, fitted jean and you're going to look awesome :)
Personally I like that A&F/Hollister syle on guys your age. You don't have to buy their clothes but if you go on their websites and look at the styles they suggest, they're almost always dressed well (aside from the flip flops to every single outfit) Right now they kind of have summer looks I think the ones they usually have for winter are better, but you get the idea
Good hygiene is of out most importance. Shower, deodorant, clean clothes, and keep your hair neat. Second, find a good, subtle scent. Invest on some colognes and non of these axe/ old spice spray crap, though since you are only 16 avoid the mature, musky ones. I recommend you check out some from CK, Lacoste and Ralph Lauren. Clothing wise, keeping it basic is actually quite attractive, and to me it just looks much cleaner. So; solid color basic tees, casual jeans, and sneakers.
hey, listen, each place has a different kind of style, and each person likes a different kind of style. I think you should look around you. See what your friends are wearing, what the more popular boys are wearing. Just to get an idea of what the style is where you live. if you like something try to find it and buy it. You can also ask people where they bought whatever you liked, it's not weird to ask.
But, you need to stay yourself and keep your own style. If you don't like what you are wearing and don't feel comfortable, people will see it, and you won't get your goal. basically, look at what others around you are wearing but stick to what you like. :)