All you need to break the code

The maximum deduction drops to $2,000 for singles earning between $65,000 and $70,000 and for married couples earning between $130,000 and $160,000. Those who earn more can't take the deduction at all. If you paid college expenses in one of the last three years but missed this deduction, as many people did, file a 1040X to amend your return and get a refund.

Educator expenses. Last year also marked the end of the educator expense deduction, which allows schoolteachers to write off up to $250 in out-of-pocket costs to equip their classrooms.

Home energy improvements. If you bought energy-efficient equipment, ranging from new windows to water heaters, you might qualify for an energy improvement tax credit. If you bought a water heater or air conditioner, you could qualify for a credit of up to $300. You could get up to $150 for a new furnace, $50 for a furnace fan, up to $200 for replacing windows and up to $500 for buying insulation materials. But the credits are good only for products bought and put in service in 2006 and 2007. (The one exception -- a solar credit that can be worth as much as $2,000, has been extended to 2008.)

Stealth credits

You won't find a mention of two important write-offs anywhere on the 1040.

Adoption tax credits. If you finalized an adoption in 2007, you can claim a credit of up to $11,390 per eligible child. The credit cannot exceed your actual adoption expenses, which include attorney fees, court costs and travel expenses, unless you adopted a "special needs" child. Such children must be U.S. citizens or residents who can't be returned to their parents. In these cases, the taxpayer can claim the full $11,390 credit, even if their adoption expenses were less.

This credit phases out for taxpayers with more than $170,820 in income. It's gone for those earning $210,820 or more. If you are married, you must file a joint return to take this credit, but the phaseout ranges are not affected by whether you are married or single.

To claim the adoption tax credit, you need to fill out Form 8839 and check the box on Line 54 of the 1040.

Hybrid and alternative-fuel vehicle credits. Taxpayers who bought one of a range of fuel-efficient cars qualify for tax credits. They vary widely based on make, model and date of purchase.

That's because the credits are based on a complex formula that involves energy savings over the life of the car compared to similar vehicles.