#1: Deducting the wrong year for property taxes
You take a tax deduction for property taxes in the year you (or the holder of your escrow account) actually paid them. Some taxing authorities work a year behind — that is, you’re not billed for 2011 property taxes until 2012. But that’s irrelevant to the feds.

Enter on your federal forms whatever amount you actually paid in 2011, no matter what the date is on your tax bill. Dave Hampton, CPA, tax manager at the Cincinnati accounting firm of Burke & Schindler, has seen home owners confuse payments for different years and claim the incorrect amount.