Well having a good sense of style is important, when you dress youself you need to think,
Am i doing this to impress other guys or girls?
A lot of people will dress like what they think "thugs" dress like, and thats their choice, but, when you do that, most girls don't like it
A good way to dress is formal but casual, but like all people, their opinions vary, so be yourself.
I usually wear polos, blue mostly (goes with my eyes), then a pair of jeans, loose but not baggy, or a pair of slacks, mostly neutral colors. Don't have colors match (Black/black, grey/grey, etc). And a pair of semi-formal shoes (like sketchers) Black or brown are good (Chicks always compliment on your shoes, you might not notice them, but they do)
My favorite stores are Express (or structure depending if they made switch yet), Anchor Blue, and some gap.
The express line of clothes is very expensive (65 dollars for a pair of pants
so i try to keep those to a minimum, anchor blue is not as expensive, but still good. The things i like about these stores is the softness of the clothes, THey have spandex in them so it gives a tight feeling without being restricting.
I just basically try to be myself, if you look nice you'll get a lot more compliments then if you look like the fad for the time ("thug style" as people call it), Looking nice always goes over well with the ladies, but if you don't want to stand out, just wear ecko and sean jean (no offense to anyone).
Remember, guys might think being trendy is the way to dress, but a chick much rather prefers a guy who dresses to kill.