Figuring out if a girl likes you requires paying attention to her behaviour, her words and her body language. You'll need to notice how she acts toward you compared with how she acts around everyone else.
Body language is one of the most obvious signs of attraction. If a girl stands closer to you than she does to others, touches you often, smiles a lot while talking with you and makes frequent eye contact, she may like you. An important part of gauging a girl's body language is to see how she acts with you compared with others, because some girls are naturally affectionate and flirtatious with everyone. If she seems more flirtatious with you than with others, however, she is likely attracted to you.
Change in Behavior
If a girl seems unusually nervous around you, that may be another sign she likes you. Perhaps she is normally cool and confident, but acts awkward or shy when talking to you. Or perhaps the opposite is true: Maybe she is usually quiet with others, but is more talkative with you. Any changes in her behaviour that seem connected to you are a possible sign that she likes you.
If a girl compliments you a lot or is very friendly, she might like you. Though some girls are naturally friendly and outgoing, many girls go out of their way to chat with and say nice thing to the person they like. Notice how she acts with others; if she acts even more friendly toward you, she probably likes you.