ESSENTIAL TIP: Look at people.

A lot of us have a hard time looking others in the eye.  Lots of reasons for this: embarrassment, shyness, cultural issues, the fact that you're lying through your teeth (OK, we'll hope that isn't one of them).  And yet this is the principle way that we make the initial connection with others, particularly in western -- and especially in American -- culture.  You could argue that until you look someone in the eye -- really look at them, not the Eye Look that's the equivalent of the Air Kiss -- you don't really see them, don't acknowledge them, don't allow them to be part of your reality.  So, cultural issues aside, look at people.  You can't communicate with someone if you don't acknowledge their existence.