Kissing is an art, and like other arts, some people are naturals, and others have to learn. There are different ways of kissing, and they should be applied separately not only to her lips, but her other parts as well. French kissing is fine for making out, but you'll find that you do it less during sex. Do NOT under ANY circumstances just stick your tongue in her mouth and wag it around. That's what Face-Huggers do in the Alien movies, not what you should do to your girlfriend. Anything you do during a kiss should have a purpose. If you use your tongue during a kiss, use it to trace around her lips or to touch the very tip of her tongue - it should never go very far into her mouth. Most women are fine with simple kissing during sex - lips parted, but no tongue action, and do it softly during foreplay. If you're kissing other parts, you can modify your technique accordingly. If you kiss her neck, do it softly, but sometimes you can throw in a little bit of teeth as a "nibble" on her neck. You can also kiss her neck passionately for a few seconds, then position your mouth just a couple millimeters from her skin and inhale for a few seconds - the warm film of saliva on her skin will be rapidly cooled by evaporation, and the quick change from hot to cold (and back again as you start kissing once more) can excite her. Kissing is something you can experiment with to a large extent, just remember the three cardinal rules: not too slobbery, not much tongue, not much teeth (if any). If you're a good kisser she will be putty in your hands.