The trick to buying on eBay is to place your bid up to the maximum value you are willing to pay, meaning that one dollar more than that amount is enough for you to be willing to walk away. And then hold to it. Too many people view the auctions as a win-lose when they should be viewed as a value setting exercise and nothing more.
I will admit that I'm one of those last minute snipers because I will watch something to see what happens on the bidding and then place my bid right near the end. The reason for that is that so many people are irrational in their bidding and as soon as bidding starts on something it turns into a competitive event. I avoid that by coming in during the last few minutes and placing a maximum bid that reflects the most I'm willing to pay. If I lose, so be it, but I've only lost a couple. After I've gotten my item, I've seen the lower bidders start on the same item from a different seller and drive it substantially higher than the one I got.
The most extreme example was a '70 Shelby GT500 convertible die-cast in Acapulco Blue. I got mine for $62.00, which was original retail. The only other one for auction then went for $85.00 2 hours later.
So my advice is to treat the auctions exactly the same as you would treat buying a part from NPD or Mustangs Unlimited. Decide what the item is worth, place your bid near the end of the auction to avoid triggering a frenzy, and walk away if the price goes above the value you placed on the item.