Consider how often she agrees to spend time with you. If you frequently ask this girl to hit the town with you alone, or even with a group of friends, and she usually declines, she is likely not that interested in spending time with you.
Watch her attentiveness to you while out in public. While this girl likely won’t spend every waking minute staring longingly into your eyes, if she is into you, her eyes will spend at least some time lingering on you. If she seems more interested in the hot dog vendor, the couple down the aisle or the little girl with a red balloon than she is in you, she’s likely not romantically interested.
Reflect upon the intimacy of the information she willingly shares. If the girl you like seems willing to open up to you, sharing with you some private details that she wouldn’t broadcast to just anyone, she likely has feelings for you. If, instead, the most intimate details you get from her are comments on the weather, she’s likely not dreaming of a romantic future in your arms.
Pay attention to what she does when you mention other girls. If the girl is interested in you, she will probably not be too thrilled when you mention interest in other ladies. If, instead, she encourages you in your pursuit of another girl, she’s likely not interested in having you as her own.
Read her body language. If this girl touches your arm when you are engaged in conversation, keeps her body turned toward you, or faces you, even if doing so means turning her back on the rest of the room, she is likely open to your romantic pursuits. Conversely, if she keeps her body turned away from you, folds her arms when she talks to you, or seems to always have a physical barrier, such as a piece of furniture, between you and her, she’s likely sending you a message indicating her lack of interest.