It can be tax-smart to time some of your financial events strategically. For example, if you have a mortgage and you pay your January bill early, by Dec. 31, you may be able to deduct the interest in your 2012 return. (If you pay your property taxes and state or local taxes before year-end, you should be able to deduct them, too.) Note, though, that some mortgage lenders won't cooperate and may apply your extra payment toward principal and not interest, or may just not include the extra payment on your year-end tax statement. Check with them first.
Similarly, if you're expecting a sizable bonus at work soon, you might ask your employer to pay it to you in January, in order to lower your taxable income for 2012. If you earn your income by billing people for your work and collecting payment, you could also delay sending out some bills until January, in order to reduce your 2012 income. Pay state estimated taxes each quarter? Send in your January payment in December, and you should be able to deduct them this year -- assuming you can itemize your deductions and you're not subject to the Alternative Minimum Tax, or AMT. Above all, consider your tax rate and whether you expect it to be much higher or lower next year -- then shift whatever income and expenses you can accordingly, to minimize your tax hit.