Read feedback ... ALL of it. Don't bid on Private auctions or where there is a seller with Private feedback unless you KNOW them.
Check out this place, and USE it:
http://www.toolhaus.org/cgi-bin/negs
This will show you what the seller is really about.
Also, remember you are trying to get the lowest price -- not see your name up in lights. Wait and wait, and then WAIT some more. Don't "bid early and bid often", you only want that if you are the seller. Look at the sellers other items, maybe they are selling the same thing Buy It Now for cheaper than you were gonna bid. Watch market pricing and use the Completed Auction search so you don't overpay.
Enjoy and don't take it too seriously.