I think you will know when they start to show more attention to you then they ever did and that they look at you when you didn't look at them.
Another AnswerWhen the girl starts to play with you in groups it means she wants to see what you are like. Also in class she may start to talk to you and if she has a new outfit or something is different about her its because she wants to impress you. If someone says to her do you like "Michael" she will say no when she actually means yes. If you like her tell your friends and let your friends tell her friends so that maybe you guys will become more then friends,
