Determining whether a guy likes you as more than a friend is always a difficult task as the only true way to know how he feels is for him to tell you directly. However, you can infer sexual attraction through interaction with one another and through non-verbal hints of flirtation. The way a male uses body language when he is attracted to someone can sometimes be very distinct.
Determine how much time you spend with the guy and how strongly the male seems to want to be around you willingly. Is he the one who calls you and asks to do activities together?
Look for obvious signs of flirtation. For example, is he acting slightly nervous around you? Are there awkward moments? What about physical contact? If he's touching your shoulder a lot in a friendly manner, it could be a sign of flirtation.
Ask the guy questions about personal stories you've told him in the past. See how well he knows you and remembers what you've said to him in the past. If he can tell you small details and recall things you've done together, it could be a sign of how interested he really is in you.
Pay attention to how much the guy tries to make you laugh or entertain you when the two of you are alone. Also, if you are with a group of friends, see if the guy is trying to impress you in front of other people by sometimes talking about his successes.
Test the guy slightly to see if he's willing to buy you lunch or dinner. Don't use the guy just to pay for you, but it's a beneficial way of seeing if he's willing to purchase things for you or go out of his way to make you happy with a small gift. Sometimes a guy might give you a sentimental gift for a birthday--such as a card, note or jewellery-- that may indicate he wishes for something more than friendship.