My recommedationS
Buying:
Figure out a maximum price and stick to it. If you can be there when the auction ends, dont place you final bid until the last 30 seconds, then bid you maximum you will pay.
Selling:
Set the starting price at the minimum you will accept, or if you are confident that it will be bid up high, like a high demand item, set the starting price at $.01. Remember that if you are offering something people want, many will wait until the last minute to bid. If you don't meet your reserve by the last day, cancel you auction, you have until 12 hrs from the end to do so.