Assume that the first bids on an item aren't real and wait until you see actual bidding going on. Some auctioneers love to start an item at $100 and then spot $200 and $300 "bids" and then when no actual people bid they go back down to $100 again and wait for an actual bidder.
I attended the Superauction last month in Worcester and noticed this technique several times. It was very obvioius what they were doing.
A few other things I noticed:
The opening bids of many games were way over the actual value. (they tried to start a Family Guy pinball at $5,000) The auctioneer would test the water, and if nobody bit, they'd keep dropping the opening bid until they got a bite. Or drop to a low opening bid and use the technique above to make it appear that there was activity.
For most items, they would let the bidding continue far longer than it needed to, hoping to encourage one last bid. The "going once, going twice" would go on for 30 seconds or so. However, if the bidding started slowly and there wasn't much action and the item appeared to be selling for a really low number, the auctioneer would pretend to end the auction - he'd skip the 'going once, twice' and just put his pen to his paper and say "okay, that's it" and repeat the last bid. At this point, all of the folks who were waiting to place a bid would immediately raise their card to put in a final bid. Now there are multiple bidders at one time, and the auctioneer would quickly hit all the bids driving up the price.
Example: the bids are in $50 increments but gets to $250 and stalls. Rather than "going once, going twice" the auctioneer appears to just end the auction prematurely at $250. Three people quickly raise their paddles. The auctioneer hits every one of them as if they are separate bids: $300, $350, $400. Boom. SO now, the guy who wanted to make one last bid for $300, actually got suckered into making a bid for $400.
The auction company were either purposely decieptful or were careless. Since they deal exclusively in arcade games, I assumed they would know everything about what they were auctioning off. At one point, they were auctioning a SF2 cab. The problem was that the cabinet was SF2, but the game inside was Strider. They auctioned it off without incident, until someone was nice enough to let them know it wasn't a SF2 game. They ended up running the bidding again for the corrected item. Should that have even happened?
I noticed these things pretty quickly, as well as a few other things that seemed a bit "off" to me. The key is to go knowing what you are willing to spend, and to check out each machine before you make a bid.