Don't bid on an auction that has several hours left. You will
get outbid. Instead, bid when the item has 5 minutes or less. Usually I
wait until the auction has less than a minute left.
Don't bid on an auction just because no one else is. Odds are there are 50 other people watching that auction too.
Bid only on auction that offer a "buy it now" option. If you don't
win the auction, you don't necessarily loose your money because you can
apply your bid dollars to buy the item.
Per #3 above, only bid on items that you actually want to buy. If
you are just bidding on the auction because you think it's a good price
you are only short changing yourself. Bid on items that you are willing
to buy using a "buy it now" option.
Don't confuse penny auction sites with eBay. You are paying for each of your bids, spend them wisely.
The best time to bid is early in the morning when people are getting
ready for work. There are still a number of bidders on penny auction
sites at 2:00 and 3:00am. Penny auction sites attract night owls, play
in the morning instead.
Don't spend more than the product is worth. This is simple but must be said, don't spend $40 in bids on a $35 item.
Earn free bids. Most penny auction sites offer free bids if you refer your friends or write a blog post about their site.
Don't gamble. Don't bid on items just to win. Some consumers bid on items just for the rush of winning after a loss. Avoid this.
The more bids you buy, the more you save. Most sites offer bids at a cheaper rate if you buy in bulk.