For alot of men, understanding girl is the biggest puzzle they'll ever have to solve. In fact for most of us at one time it was. Luckily for me I was able to crack it, however not all men are as lucky as me and are often confused around girls.
So heres a small list on what to watch for when you are in a conversation with her:
1. Her smile, if you encounter a girl and start small talk and she's smiling, well she's interested in what you have to say. Basicly she opens her door to be accessible.
2. Her hair, if she fixes her hair when you are talking to her it is a sign of interest into you, do not take this as foolproof but it is a sign that she's getting attracted to you my friend.
3. After like 5 minutes of talking you can start "touching" her, like a pat on the shoulder and after jokingly saying "You would never do that huh? :P" Basicly see it that way, if she rejects a simple pat, how the hell will you be able to hug her, kiss her and get in bed with her?
So thats pretty much 3 simple trick that you should lookout for, if you ever need more answer just put a comment and I'll edit my post :) Thats it for now