Even though I always think I will avoid it, I seem to have no problem attracting and sleeping with/dating women at work.
I'd advise against it because of the drama involved, but if you think you must, I will tell you what worked for me (even though I wasn't really trying).
Basically, DO NOT ask her out. Continue with the flirting. Go out to after-work drinks with the office sometimes, sometimes go home when everyone else goes out. Whatever you do, don't make it look like you're looking for an actual "date," because even a whiff of that might ruin whatever fun you two are having through flirting, or whatever fantasy she might be considering with you. And enjoy the thought of having someone there to flirt with every day. Be subtly pervy but don't get into trouble.
And don't just flirt with her. Flirt with every girl in the office. Old women, married women, ugly women. Be known as the guy in the office who flirts and women think is funny. (Just don't cross any lines.)
Finally, rid your mind of any expectations of getting together with this girl. The more free you are mentally, the more confident and charming you will be. Just tell yourself, "she's cute, we can flirt, but we work together."
In a nutshell, be the fun-loving guy and DJ you know yourself to be, and pretty soon this girl and some others will probably start thinking about throwing themselves at you, until they can't hold back. Like I said, it's happened to me at different jobs, and the main reason was because I stayed non-chalant and flirty and reasoned with myself that I wasn't going to be hooking up with anyone at work...and then it happened anyway because it was so easy. This included some great experiences with my hot boss in her office. A lot of fun but a lot of drama so be careful!
