How to I initiate a kiss?

Heres my situation: I asked this girl to hangout with me and we ended up at my apartment watching a movie on my bed. Now this was only the 3rd time we met. Whats a good transition from just watching a movie on my bed with a relatively new girl, to start kissing? Obviously, if she was sittin there next to me, she is open to the idea. Whats a good way to kiss her without making it awkward or ruining any future prospects. Please be specific and give details if possible.