It's really just all about body language and context. However, starting from the mild and working up to the wild.....I'm kinda tired, so bear in mind I may be talking out my ass.
Peck: about like it sounds...like a bird pecking at something. Short, sweet, to the point, and no slobberage.
Thank You: On the cheek or on the lips. Sometimes elsewhere, but that's best saved for a different thread
. Tends to last a little longer than a peck, you might get some saliva on you.
French Kiss: Tongue is involved. Slobber is as well, to some extent.
Romantic or lusty kisses are different because well....there's a difference between lust and romance. Romantic kisses are....romantic, and lusty kisses are....lusty. Sorry I didn't explain that one too much, it's just kind of one of those things that just happens when the time is right. (and if the time isn't right, you're likely to have to polish your ass kissing techniques) If you start kissing and feel a serious mutual "do me now" vibe, that's a fair indication you are experiencing a lusty kiss.
In all honesty, the best kisses aren't the ones that are planned out in advance. They just happen. Good luck and have fun!