Here's my best advice for using eBay : click on this .  This will take you to the auctions ending today (which is all you really want to bid on), and let you choose your category.  This is the secret of eBay!  And now, you have your finger on the button!

ALWAYS, ALWAYS, ALWAYS READ THE FEEDBACK OF THE SELLER!  This will help you make smart decisions as to dealing with or NOT with the seller.  Also, remember that if someone has sold 4000 items give or take, and has a little negative feedback, they are still likely to be a reputable seller.  YOU CAN'T PLEASE ALL THE PEOPLE ALL THE TIME :) .

 And use PayPal to pay for your purchases; it really speeds the delivery of your goods.  PayPal is better than ever with EBay taking over the reigns. 

Sign up for EBay, and use the watch feature that comes with your free account.  You can view so many facts at your account including the history of your buying and selling activities past and present.  Don't bid on things when there is 5 days to go, just click on watch this item, and check back until the last few minutes of the bidding.  It's great fun to bid!