How do guys flirt?

no not really. sometimes if the guy likes you he will make fun of you but not in a mean way. also he will treat you just like the guys. just to let you know he's comfortable with you.

Body language? No. Not at all. For me, its through joking and messing around mostly. I generally treat girls who I'm cool with like "one of the guys". If I like a girl, I tend to try hard to hide it until I know whether or not she likes me so I overcompensate and go OUT OF MY WAY to make it seem like I'm treating her as "one of the guys." So, if you're a girl who I'm cool with, I treat you just like I do my guy friends. But if it seems flaky, like I'm forcing it, that's cause I like you.

I usually just try to be around the girl, without being a stalker. And I'm really shy, so it takes me forever, and I probably end up looking disinterested or weird if I don't say anything but I'm around.

I saw my big crush last week, and I gotta say, I'm really nervous around her, but I did get out a VERY quick conversation - it amounted to small talk, and I couldn't think of anything else, so I just stopped talking when I should have talked more. I have no idea what to say unless there's something funny that I can use, there was nothing, so I just shut up.

Even the shy ones will try flirting. As far as body language, I think we try to show off a bit, so if we're looking good at a party, we're probably trying to flirt with SOMEONE. I think that if we're around, and not enough to be a stalker, but we're being shy, then that's a sign of possible interest.

Blushing is another hint, though it's not a definite sign, because I blush like crazy, even when I'm not interested. I get a compliment and I turn red.

Then there are the others, like pupil dilation, heart beating faster, etc.

Yes they do sometimes looking down or blushing,