The Internal Revenue Service today reminded last-minute filers to avoid the late-filing penalty by filing either a tax return or an extension request by April 15 and  to review their tax returns for common errors that could result in processing delays.

Last-minute filers typically make more errors,” said IRS spokesman Dan Boone. “Using tax software, including IRS Free File, will eliminate most mistakes.”

Here are some ways to avoid common tax return errors if you’re rushing to meet the April 15 filing deadline.

File electronically. If you e-file or Free File, tax software will do the calculations, flag common errors and prompt you for missing information. Plus, you get confirmation that the IRS has received and accepted your tax return. If your 2009 income was below $49,000 or you are age 60 or older, let IRS-trained volunteers do your taxes and e-file them free. Call 1-800-906-9887 for the closest help site.

Remember Making Work Pay. The Making Work Pay tax credit –– available in 2009 and 2010 –– is worth up to $400 for individuals and $800 for married couples.  Most people got it as a reduction to their paycheck withholding. Form 1040 filers must complete Schedule M, attach it to their returns, and claim the credit to benefit from it. (Tax software handles these calculations automatically for e-filers.)

Retirees Who Worked in 2009, Read This! If you received the one-time Economic Recovery Payment, you need to report the payment on Schedule M. Taxpayers who are not certain whether they received the economic recovery payment can find out with the help of an online tool, Did I Receive a 2009 Economic Recovery Payment? If you don’t have access to the IRS Web site, call 1-866-234-2942.

Claiming the Homebuyer Credit? If you claim a homebuyer credit, complete Form 5405, and include it along with the settlement document, such as a HUD-1. More information is available on the homebuyer page at IRS.gov/recovery.

Double check all figures. While software catches and prevents many errors on e-file returns, math errors remain common on paper returns. All filers should make sure they enter their Social Security Number correctly as this tends to be one of the biggest errors every year.

Get the Right Routing and Account Numbers. Make sure the financial institution routing and account numbers you have entered on the return for direct deposit of your refund are accurate. Incorrect numbers can cause your refund to be delayed or deposited into the wrong account.

Sign and date the return. If you are filing a joint return, both you and your spouse must sign and date the return. E-filers can sign using a self-selected personal identification number (PIN).

Attach Forms To the Front of the Return. Paper filers need to attach W-2s and other forms that reflect tax withholding, as well as other necessary forms and schedules, to the front of their returns.

Avoid penalties by paying as much as you can now. A number of e-payment options are available. Or send a check or money order payable to the “United States Treasury.” If you owe $25,000 or less and can’t pay it all, set up an Online Payment Agreement at IRS.gov.