#9 He is continually trying to downplay himself and talk other people up. A guy who likes a girl wants to make themselves the most irresistible and awesome guy in the room. If he isn’t trying to impress you, then he is trying to get rid of you.
Once more, if he is trying to talk one of his friends up to you, then either his friend has a crush on you, or he just is trying to distract you and push you off on someone else. Either way, that is a clear sign for knowing how to tell if a guy doesn’t like you.