I don't ebay much, but every once in a while I make a bid of what it's worth to me when I see something I'd like.
Really folks, you don't WIN anything; you just prove that you're willing to pay more for something than anybody else in the world.
The SELLER wins.
Some good advice here and some I do not agree with.
Like Chuckk, I decide what I want, I bid what I am willing to pay and that's it. However, I do win the bidding competition, not the item, so I do, in a sense, Win something.
The seller does not always win! In fact, the seller is often the only looser, if the item does not sell. There are no buyers, but the seller still had to pay Ebay's listing fees. Ebay is the only for sure winner, in my opinion.
As far as bidding goes, I put a minimum bid in, as soon as I see something I want. That bid remains unaltered, by me, until the last few seconds of the auction and then I deliver my top offer. After that, I wait, with breath held, hoping I win the competition and, ultimately, the item.
As for not wanting to wait until the end of an auction, the snipe thing is very popular. Personally, I have never used the system nor do I intend to. As someone else mentioned, bid dueling, during the last few seconds of an auction, once again with bated breath, is, indeed, fun!