Two weeks ago, I wrote about mistakes sellers make to kill short sales. Buyers also end up ruining these deals or making things more difficult than they need to be. Here’s what they need to avoid:

Not doing enough research on the seller and the mortgage before you commit. Are the husband and wife getting a divorce and will both spouses stay cooperative all the way through? Do they have two mortgages, which will make the negotiations with the bank more difficult? If you sense the deal could drag on longer than a few months, find another house.

Failing to check up on the seller’s representative who will negotiate with the bank. The key to completing a short sale is checking in with the bank at least weekly. Otherwise, the case will stall because the lender likely has thousands of other short sales to consider. This short sale probably isn’t the only one your seller’s rep is negotiating. So don’t be shy about insisting on regular updates.

Being too picky on price. If you are trying to get the deal of the century and the bank wants a little more money, it probably makes sense to kick in the extra cash. There’s no use in walking away from a steal just because you have to pay a little more. That’s the kind of thing buyers tend to regret later.

Spending money before you have to. After you sign the contract and wait for the bank’s approval, don’t start ordering inspections and appraisals and applying to the homeowner’s association. If the deal doesn’t go through, you’ll be out that money and very unhappy.

Getting caught flat footed on your own mortgage. Once the seller’s lender accepts your offer, it likely will want to close within a month or two. That could be a problem if you don’t have your loan approved. There’s plenty of time to get that done while the seller’s bank is considering your offer.