Adding to #1 on AZBroker's list, "Be Prepared"...
One way of making an excellent first impression is to learn something a bit personal about the person you're meeting... You can usually do this with help from the web.
For example, suppose you find out your contact is very proud of his or her daughter, who is going to college on a basketball scholarship. Find out how many points she scored last season, or last night's game and tell him/her that you read about her success.
Not only do you put your contact at ease, you do so in a way that will encourage him or her to be a bit more upfront in his/her conversation.