I'd say put her out of your head when your not actually with her, until after you've shagged her. We've all made that mistake, and it just means you'll end up fantasizing about her non stop and feeling wick if you don't end up riding her. When your chatting be confident about everything, tease her lightly, try and like lead her through doors with your hand on her back and get her hi fiving you/other light touching things, cos if she doesn't feel your touch it'll make it more awkward if your going in for a kiss etc. when you know she likes you (chats to you a lot, smiles, you'll know) get her number and invite her round to watch a DVD or to the cinema or something.
If it gets to a stage she doesn't seem interested, just stop chatting to her or caring about her to avoid getting into a "friend zone" thing where you want to ride her and she teases you but never gives you any action. The best policy is not giving two ****s about her till after you've bucked her. That's my advice anyway!