Body language involves many gestures and movements, and each one with different meanings. It is a complex method of communicating. But the art of body language is that when you learn the interpretations and indications of different body signals, you are able to determine one's inner feelings and emotions. Thus you can control the situation by knowing how to react in advance.
When one can maintain the eye contact and even prolong it, it is indicative that his focus of attention is in listening to the other person. The inability to maintain it has many meanings, depending on the situation. When there is sudden breakage of eye contact and the eye wanders off to another direction, it may mean that he is distracted by a certain object, like another person entering the room. It may also mean that he is losing interest, getting bored, and would like to get out of the conversation.
The eyes are also used in flirting, especially in knowing if the person is attracted to you or not. When your eyes meet across the room, and then one of you looks aways but looks back, it is a signal of attraction. It is also reflected when the eyes would go down to the lips and then back to the eyes again.
If the eyes would look up to the forehead of another person, it means he is talking to someone with superiority. When the eye would go down to the nose, it means that there are no figure of authority in both parties.
There are two meanings of handshakes. It can show confidence, or the exact opposite, shyness. Confidence is evident in a firm handshake with the hand pointing downward. The palms should also come in contact with each other. On the other hand, a weak handshake with the hand pointing upward indicates shyness or nervousness.