Watch it and then bid in the last few seconds. ebay doesn't extend the finish time for an auction when someone bids so others don't have time to react to your bid and out-bid you. The snipe bid should be the max you want to pay for the item as you won't have time to place another bid either if there should be a hidden proxy bid that is higher than your high-bid.

There are services you can pay to do the sniping for you but I think that's cheating. You can easily set a timer to remind you if you want and place the snipe-bid yourself. ebay has made changes in the bid protocol to make it easier to do manual bids. Year ago, you were at risk of the ebay computer getting busy and not confirming your bid; these days that never happens.

Sniping favors the bidder to the detriment of the seller. Final sales price will on average be lower than otherwise. However, if every bidder placed his max bid earlier in the auction, there would be no advantage to sniping and average sales prices would be higher.