Most Helpful Girl
Be her friend first, and avoid being too clingy, like I used to do. You can see if she's interested by looking at the signs:
-Coming up to you or texting you first
-Telling you personal things
-Laughing at a lot of your jokes
Those are just the basic ones. But more than anything, take it slow and use social awareness to your advantage, because reading people is a great way to see how you can talk to them.