Kiss lots. As for tips, my biggest one would be to "go with the flow." No 2 people kiss the same way, so its best when you kiss someone new to let them do a little more of the action and find out how they kiss. Then adjust yours to match. Its kind of an art form actually.
Also, don't eat their face. By that i mean don't open your mouth as wide as it'll go and attack them. And shoving tongue into their throat as far as it'll go is also bad.