If you are losing to another bidder, there is probably no shilling happening.
Shillers do not want to win. That means the seller pays fees not to sell his product.
They want you to win at the highest possible price.
If you are winning by a single increment, well, that's how auctions work.
You bid until you reach your budget. Then you stop.
The underbidder in every auction is just one increment below the winning bid.
The thing to look for is bidders who top your bid, then retract.
And if it only happens once, well, sellers spend a lot of time here moaning about bid retractions.
But if there is a pattern, then you may have a shiller.