If you ask someone a question and they only partially answer just wait. If you stay silent and keep eye contact they will usually continue talking.
I really like this. Silence makes people uncomfortable. Use it to your advantage.
It will backfire on me, it will make me feel uncomfortable.
Love this one, use it all the time. One of my friends read about it somewhere, and he immediately turned to me with an accusatory glare.
This is useful everywhere too. I used to work as a debt collector (yeah, I hate me for it too) and it was one of the first tactics they taught us. Now I'm in a medical career...and same thing. It's invaluable when interviewing patients because you can get so much useful information that you never would otherwise.