lower cut tightish shirt that shows just enough cleavage but still gives you a bit of innocence. Tight pants like skinny jeans to show off your bum and legs. Also a bit of makeup like subtle colors to accent your eyes and a little nude or semi nude lipstick .It's like sexy innocent, you look hot but still feel comfortable in your skin.
Style your hair. Your hair doesn't look bad, but it's a little too "natural" looking. Either have it sleek, stick straight or curly/wavy. Either way plan on spending some extra minutes in the morning with some hot tools getting ready
Wear more dramatic makeup. Smokey eye/nude lip is always hot. line your eyes and wear more eye makeup
Show more skin. Wear tighter clothes, go shopping often so you keep up with trends. Wear short shorts/dresses/skirts, wear low cut clothes. Accessorize more. This is my biggest pet peeve how some girls will have a decent outfit and NOT accessorize.
play with your outfit, you can wear a skirt perhaps with a nice top.. so that an outfit will not look slutty I think the common general rule there is that you should only have one focal point like when you wear a short skirt, don't pair it with a revealing top or when you wear revealing top pair it probably with pants etc. :)
Wear shirts that show off more of your clevage like v neck tees. Also wear necklaces with them because it gives off a sexy flair. Also wearing a natural smokey eye with pink or nude lips with rosy cheeks and that gives off a sexy yet slightly innocent image. Also wear RED, red is one of those sensual colors and also wear jeans that are tight fighting like skinny jeans.