The most-overlooked tax deductions

1. State sales taxes.
Although all taxpayers have a shot at this write-off, it makes sense primarily for those who live in states that do not impose an income tax. You must choose between deducting state and local income taxes or state and local sales taxes. For most citizens of income-tax states, the income-tax deduction is a better deal.

IRS has tables that show how much residents of various states can deduct. But the tables aren't the last word. If you purchased a vehicle, boat or airplane, you get to add the state sales tax you paid to the amount shown in IRS tables for your state, to the extent the sales tax rate you paid doesn't exceed the state's general sales tax rate.

The same goes for home building materials you purchased. These items are easy to overlook, and these add-ons could make the sales-tax deduction a better deal even if you live in a state with an income tax. The IRS even has a calculator on its Web site to help you figure the deduction, which varies depending on the state where you live and your income level.

2. Reinvested dividends.
This isn't really a deduction, but it is a subtraction that can save you a bundle.

If, like most investors you have mutual fund dividends automatically invested in extra shares, remember that each reinvestment increases your "tax basis" in the fund. That, in turn, reduces the taxable capital gain (or increases the tax-saving loss) when you redeem shares. Forgetting to include the reinvested dividends in your basis -- which you subtract from the proceeds of sale to pinpoint your gain-means overpaying your tax.

3. Out-of-pocket charitable contributions. It's hard to overlook the big charitable
gifts made during the year, by check or payroll deduction (check your December pay stub). But the little things add up, too, and you can write off out-of-pocket costs incurred while doing good works.

Ingredients for casseroles you prepare for a church or nonprofit organization's soup kitchen, for example, or the cost of stamps you buy for your school's fundraiser count as a charitable contribution. If you drove your car for charity in 2008, remember to deduct 14 cents per mile (or 35 cents a mile during the first half of the year and 41 cents per mile for driving during the last six months to aid victims of the floods and tornadoes in the Midwest).