One fundamental element of body language is eye contact. When we look people in the eye, we are showing them respect and that we are interested in what they are saying.
It also shows that you are an open person and have nothing to hide. A good general rule is to maintain eye contact two-thirds of the time.
If you have much more eye contact than this, you can be too intense. On the contrary, if you avoid eye contact, people may think that you're not interested in them, or that you are not a sensitive person. And you don't want to give that impression, do you?