Think about what the popular guys wear. What are popular clothing stores in your area? Around here American Eagle, Hollister, Abercrombie, etc. are the rage. If you're not sure how to put together an outfit, go into one of the "hot stores" and look at the mannequins. Hell, most of the time the chicks working there will put together an outfit for you if you ask them. If you can't afford 'em (all the stores I listed are terribly overpriced, and IMO played-out) look at the things there and find cheaper versions in other stores or on the internet.
Read some fashion mags, check out websites, just research. Being well-dressed isn't so much having all the latest styles, it's more like looking like you actually put some thought into what you're wearing. Generally I know I'm well-dressed when I look in the mirror and I can feel confidence just beaming out and I think "Damn! What a sexy man" lol. Most importantly of all, wear clothes that FIT RIGHT. Not to baggy, and not too tight.
And I doubt that all HS chicks care about is looks. True, looks do matter, but nowhere NEAR as much as you think they do. Looks may get your foot in the door, but if you're a chump they'll still blow you out.
