I don't know why it is so embarrassing and uncool these days to show someone that you like them. It's not that deep. Let's grow up a little bit and appreciate the things we do for the apple of our eye.
1. Puts herself in your line of sight
If you keep seeing the same girl over and over... she's crushin'. Girls are creepy. Girls that deny this are the creepiest ones. Exposed! She will pay attention to the fact that on Wednesdays you eat lunch at Chick-fil-A. You can bet your bottom dollar she will be seated at Chick-fil-A every Wednesday.
2. Smells good anytime you are around her
Perfume is expensive. You think she smells like roses all the time? Heck no, boy, she's spending that moolah for you.
3. She pretends to understand what you are talking about
Sometimes the male species starts talking in a different language. I am truly amazed at the amount of sports statistics that guys can spit out at any time. I'm going to take a safe guess at the fact that she could care less about your favorite team's quarterback in 1987, but if she likes you she will act interested. This will generally die away as you both start to learn what you have in common to talk about.
4. Her friends are around you a lot
You should know that her friends know more about you than you'd like. They will also hype her up her confidence. Her friends will be around you if she isn't around to see what you're like. You should probably be more worried about what they think about you.
5. She doesn't try to hook up too soon
"Too soon" can be different for everyone, but if she's trying to hump on the first date... run. That means she is lusting for you, not that she likes you. Girls that you have to work for are worth the wait. Plus, you want to be with a girl that respects herself enough to make you work for her.