How do I get over my crush?

The first thing I would do is communicate your feelings with her.  You are assuming that she is not attracted to you. However, that is not a fact.  It's coming from your own insecurities. If she does not have the same feelings then I would pinpoint why you are attracted to her in the first place in order to remove the mystery and become aware of what it is. It will help you understand why you should not act on it.

Second, I would redirect my feelings when spending time with her. Whenever it comes up in your mind think about why you are such good friends and how that is important to you. 

The third thing I would keep in mind is how that attraction if acted on can create issues and could break up the friendship in the long run. Think about how it can be destructive.

Fourth thing is to take some space. Take a few steps back from hanging out often and refocus on other things.

The last think I would do is start dating other people. Maybe take that extra time from taking space and go out on dates with others. This will help you understand if your attraction comes from a place of being lonely or if it's really authentic.

Sometimes we feel attraction to our friends out of a place of feeling lonely. This is why dating other people may help you understand more if this is just a passing phase because she is the closest person to you. It is nothing to be ashamed of and that is why it's important to let her know what is going on in your head as well. This way if you have to pull away she will understand why. Attraction on her end cannot be forced. However, you are basing her lack of interest in you off of an assumption and not a fact. You will never truly know unless you let her know that you have stronger feelings for her.  You may think you are not good looking but other people may feel differently.