instead of opnening a blank document in photoshop, use a pen and paper and write things down, photoshop kills imagination dead.
try to do cutouts of all the elements of your website with card and lay them out, juggle them around and see if you get ideas
good luck, but reemember, good design takes time.
and also because of your taget audiance of teens you might get away with doing a table based design (slapping myself now) but think about it.