Forgetting a W-2 or 1099: The IRS does an effective job in comparing W-2s and 1099s they receive from organizations to the amounts you claim on your tax return. If they do not match, rest assured you will receive a notice in the mail asking for clarification.

Duplicate dependent reporting: If more than one tax return claims the same person as a dependent, the second return will be rejected. The IRS does not try to determine which tax return is correct. They leave that up to you.

Forgetting a name change: If you fail to change your name with Social Security after marriage and you file a tax return with your "new" last name, be prepared for either a rejected tax return or an adjusted tax return.

Other missing information: When preparing your tax return, often the return is held up because key information is missing. These missing items range from property tax and mortgage interest statements, to 1099s and W-2s.

Signing the e-file authorization form: Your tax return cannot be e-filed without proper authorization. After reviewing your return, a properly signed Form 8879 must be received.