Direct eye contact shows the full interest in the interlocutor and respect for him, but if you look running, it indicates that the person is concerned about something, he at a given time is absolutely not interested in the affected subject. Try switching to something else or even move this conversation if it is important. Lookup gives a man irritation, contempt towards the opponent. The opposite view, down - it's a definite sign of discomfort, inconvenience. Vacant look at all speaks of disinterest, as in the interlocutor, and in the subject.
Quite interesting and profound observation is to determine more accurately the direction of gaze. Up and to the right - in the minds of the interlocutor there is some pattern; the upper left corner - an attempt to imagine what had never heard of; the lower left corner - dive into personal emotions and experiences, possible depression, apathy; the lower right corner - internal monologue human abstraction or as intense intellectual activity related to the subject of the conversation.