The Signs A Man Is Interested
The Eyes

Humans have the ability to say a lot with our eyes, as they are the most dominant facial feature and our focal point when communicating with one another. The look in a person's eyes is a huge indicator for attentiveness; if he manages to lock eyes with you for a longer period of time, this shows that his desire for you is strong.
Be aware though, as you may not notice when he has set his gaze on you, as men tend to stare at an attractive women even when she is not reciprocating. When he moves toward you and subtly touches you while looking deeply into your eyes, it is an even bigger signal of his deep fascination for you.
Listening

It is relatively well-known that most humans have short attention spans and will only listen to someone if we are interested in what is being discussed. If you find that you're having a hard time finishing a sentence without him interrupting you, it is generally not a good sign. However, if he is attentive, obviously listening, and furthering the conversation, chances are he is into you.
This visual sign is especially important because it is an indicator as to whether he actually cares about you or is just looking for some female action. By listening to what you have to say, he is showing you that he is intently listening and cares about your life. Furthermore, if he can remember what you two talked about at a later date, that is an even bigger measure of his interest.
This sign can show that he is falling for you because he cares enough to listen to what you have to say, and bank it as important info for later.