It's pretty safe to say that "form fitted" clothing is the way to go. Form fitted could mean different things for different types of forms (obviously). If you're already an attractive girl, being "hot" is simple: wear clothes that show off your best features (for instance, if you have a nice butt and legs then tight jeans, slacks or yoga pants are always a crowd favorite.) Accent what its attractive about you while covering up what's not. That's pretty much the name of the game.
Clothes that accentuate the female figure, and are fitted. Good hygiene and grooming. Smiling and giggling. Walking upright with a big of hip swing. Smooth skin. Work out. Look like you're feeling good and having fun.
Wear what you want but Robin (from How I Met Your Mother) is not all that busty and I love what she wears...might want to check out some of her outfits from the show
Having a preppy style like hollister and abercrombie (which are my 2 favorite stores ;)) is an awesome way to start. Now, in order to look hot. You gotta have a really nice, curvy, body with perfect cleavage, and nice, sexy legs and sexy, skinny arms to go with that preppy style. That can be done through diet and exercise. TRUST ME. Guy love that.