As an awkward and generally lonely kid. I didn't have much experience kissing people growing up. I learned (almost) everything I needed to know about kissing before I actually kissed a person because of movies. These three scenes (from separate movies, of course) will teach you everything you need to know about kissing a person.
The scene above from Shane Carruth's Upstream Color is probably the most passionate kiss I've seen in a long time. Carruth shoots the action from farther away than most kiss scenes, allowing us to see the body language of each character. The importance isn't the action of kissing but the way the characters feel about the kiss they're experiencing. The nervous moment where they back away from each other and try to compose themselves let us know that they want to be doing what they're doing but don't know how to properly approach it. I don't know about you guys but I've definitely had that terrible experience where the person that I'm kissing isn't as into it as I am (these experiences end in the realization that we aren't into each other, an awkward laugh, and then the decision to play video games. So, it still sort of ends well). But this scene shows that kissing someone and wanting to goes a long way.
This scene from Garden State puts a whole lot of emphasis on where the two characters are when they have their first kiss. By filming this scene in this setting, we get this contrast of nature and human connection. As much as we'd like to believe that we're in control of our lives there's a lot that we aren't in control of; and in the case of this film that's represented by the rain. The characters back control of the scene by doing the one thing that nature cant control: physical, human connection. Having been in a similar situation, there's something extremely freeing about making out in the rain. The world around you sort of fades away and even though you and your person are probably cold and drenched, you still have that warmth, that human heat that feels so comforting.
This is probably the most important thing on this short-list. The best part about this scene from Adventureland is the way Jesse Eisenberg's character asks if "it is okay" right after he kisses her without asking. The implication here as that if Kristen Stewart's character said "no", then he would have stopped. As the scene continues and things start "heating up", so to speak, he continues to ask questions getting consent from Stewart's character. There is nothing worse than being a human person that assumes it's okay to kiss somebody when they don't want to do that. Okay, yeah, sure, it might feel super awkward to ask "is it okay if I do this thing to your face with my face", but it's an important question and the person you're with will probably respect you whether or not they say yes or no. And, it's always been my personal belief that it's better to be awkward than an asshole.