How Do I Become A Better Salesperson?

I work in retail (At Hot Topic) and because I am still in school, I only work about 1 or 2 days a week; the rest of my co-workers, however, are all over 18, so each of them typically work 5+ days a week. As I don't have as much practice as them (I have only been working there since December '08) and don't have a chance to get a whole lot better because I am working such limited hours, what are some quick ways to better my sales techniques? What qualities or sales points would entice you most to buy something from someone? All help is greatly appreciated!!!