Personally i would recommend a Joan Jett kind of look, which is a quite simple look. Just wear leather tight trousers with a tight tee and a leather jacket. Accessorise with a studded belt and some studded braceletes. Converse all star (or boots if you want to wear heels) and lots of black eye liner to complete the look. This is the most fashionable rock look at the moment, as Jean Paul Gaultier was inspired by Joan Jett's style for his new collection and The Runaways movie came out recently.
In case you want something else, here are some other suggestions of mine;
You could do something like a 60s hippie rock look by wearing some flare jeans with a knit blouse and big round sunglasses with coloured lenses. Plus, lots of necklesses, rings and bracelets. Look for Janis Joplin to see more about this look in case you choose it.
Another look is the 70s punk which is a quite trashy look but in a good way. Shreadded jeans, stripes, tartan, fishnet, safety pins everywhere and jewellery made from things everyone has at home like earings made from paperclips or small keys (you heard right! It was a crazy time back then) Dr Martens and Converse all star are the safe choices but since you are a girl i would recommend sandals with really high heels conbined with some black fishnet tights or stockings and an extremely short skirt. A leather jacket is a must and so is the veeery dark make up (red lipstick, LOTS of rouge etc). Look for Nancy Spungen if you need some more inspiration on this look.
The easiest look of all would be the gothic one, as the only thing necessary is to wear black clothes and very dark make up.