Are you guilty of making any of these goofs on your return?
From MSN.com:
Year after year, the IRS sees Americans committing the same sorts of mistakes on their returns. Many of these errors are easy to avoid; some are more complicated.
Claiming the wrong status
Sorry, you can't just choose to file single or married. Your marital status is determined as of Dec. 31. Anything before that date really doesn't matter for tax purposes. If you're married you file either jointly or married filing separately. You may qualify for "head of household," but you have to satisfy all the requirements. You don't qualify just because you consider yourself the head of your household. In fact, you can't be head of household if you're married unless you qualify as an abandoned spouse.
Claiming the wrong status could kill your eligibility for the child tax credit, the earned-income credit and exemptions for dependents. Check out the instructions for Form 1040 detailed information to help you select your correct filing status.
Omitting or using wrong Social Security numbers
The Social Security numbers you list for your dependents, the earned-income credit and the child tax credit must match your dependents' Social Security cards. Otherwise, the IRS computers will reject your credits and deductions.