The first kiss is no big deal. Keep that in mind and it'll make things a lot easier for you. If you've been moving things forward with teasing, flirting, social proof, kino escalation or any other attraction building techniques, then the first kiss is just one more baby step. Just to make sure, it's good to give her a kiss test to avoid any potential awkward moments...
Here's an easy kiss test you can use to determine whether she's ready to be kissed or not. Lightly stroke her hair with your fingers and ask her "what kind of shampoo do you use?" When she answers, you can also move your head in closer to hers and smell her hair. If her body language doesn't pull away from you, then you know she's ready for the kiss. Touching a woman's hair and especially smelling her hair is very intimate to her and she will only allow you to do this if she feels very comfortable around you.
Another thing you can do is ask her "Hey, are you a good kisser?" However she responds, just go with it and keep the conversation flowing. You might add something like "You know, I can tell a lot about a girl by the way she kisses a man". I then might playfully turn my face to the side and point to my cheek, non-verbally instructing her to kiss me. Here, she might just give me a quick peck on the cheek in which I would proceed by busting her balls. Something like "Wow, seriously girl. That was the lamest kiss ever. 2 out of 10...maybe 3 tops." From there, she might try to give you a better kiss on the cheek the second time. Better yet, she might challenge you to beat her score of 2 out of 10 by asking you to kiss her on the cheek. Regardless, you know she's into you at this point.
If she signals for you to return the favor and kiss her on the cheek, do it very slowly and romantically. Slowly move her hair out of the way exposing her cheek. Hold her arm with one of your hands as you softly pull her closer to you and very softly kiss her on the cheek. Hold your lips on her cheek for a couple seconds. Even add in a little whisper in her ear after the kiss. Something like "I know you liked it" or "mmmm...you smell good". Of course, don't be too serious with this, but make sure your whisper is very sensual using a slow, deep voice. After you pull back, give her a sexy smile :) She will love this!
Now that she's ready (she passed your kiss test), it's just a matter of going in for the kiss when you feel the moment is right. The above are just a couple of kiss tests that can give you higher levels confidence when you go in for the real deal. Remember, whenever you go in for the kiss, do it with intention.
Even if you haven't played the situation perfectly, going in for the kiss with confidence and conviction will often be enough to instantly create that romantic movie moment for her. This is a very powerful moment for a woman and by doing this, you are giving her something very special.