I love to kiss, as long as the guy is a good kisser. Some guys are, and some aren't. Like anything else, you get better the more you do it, and to experience kissing different guys will give you a sense of what is good and what isn't.
Tongue can be good, as long as it is soft and easy - you can't get too aggressive with your tongue to start out, but it's cool to get more agressive with your tongue as things heat up.
And, move your lips, don't just press them against his and hold them there - gently caress his lips with yours, I like to get his top lip between mine, then he can get my bottom lip between his.
It is difficult to explain how to execute a "good kiss" - like love, you'll know it when you experience it.