Slowly pull your lover's tongue into your mouth during a kiss and gently suck on it. You'll stimulate all kind of underused nerve endings and maybe get your partner's mind racing as to other body parts you may give the same delicious treatment to.
Give Lips a Licking
Many awful kisses are the result of an over-reliance on your tongue. Your lips boast more nerve-endings, so make sure you give them the treatment they deserve. Lick your lover's upper and lower lips playfully. If all that licking has gotten you two lovebirds going, try gently sucking your lover's lower lip into your mouth and lightly biting down on it. Just don't get too rough.
Consider: if you always have your tongue in their mouth, they never have theirs in yours. Remember that kissing isn't a power play or a time to show off. Make sure you're cooperating in your kissing. If that's a problem for your or your partner, make kissing into 'follow the leader' kind of game.
Be a Tease
No one says you've got to be engaged in deep-throat tongue twining the whole time. Lightly brush your lips against your lover's and then pull away. Plant a sweet kiss on her nose. Nuzzle his chin. Whisper something naughty into an ear. Repeat as needed.
Keep It Simple
You're better off bagging any elaborate tricks, if you can just master the basics. Be natural. Keep your movements light and soft... at least at first. Simple and sweet is sexier than trying to duplicate some movie-star make-out session.