If a man is interested in or cares about how a woman perceives him, he will change his body's positioning unconsciously.
If you notice his body is almost always directly facing yours it is a possible sign of attraction toward you. Pay attention to his arms and legs as well. If his legs are uncrossed or open toward you, this can be an unconscious signal of attraction. If he is attracted to you, his arms will usually be out to the sides, not covering his body. In addition, the palms of his hands should tend to face you rather than away from you.
Pay attention to how close he stands to you when you two are together.
If he is a Westerner, a closeness within 3 feet of you could indicate that he likes you. There are two reliable ways to use distance to tell how he feels about you. First, try moving closer to him. If he does not reestablish the initial distance, it is possible he likes you. Second, observe how far he stands from others when he talks to them. If that distance is noticeably farther than the distance he stands from you, it is possible he wants to get closer to you, relationship-wise.
In general, more eye contact means he is interested in you.
One method of observing the eyes to look for signals of interest is to watch when he makes eye contact with you. If he makes more eye contact with you when you are speaking than when he is speaking, it is possible he thinks highly of you. Also, pupil dilation is often an uncontrollable signal of interest.
Although language can be controlled and is therefore less reliable than nonverbal signals, you can still use his language as clues to the answer as to whether he likes you.
If he teases you, creates pet names for you, addresses you directly, and often talks to his or your friends about you, it is quite possible he is interested in you.