The countdown to Tax Day is on. It's just one week away, on Tuesday, April 17th. (The usual Tax Day of April 15th is a Sunday and Monday the 16th is a holiday in Washington, D.C.)

Every year tax professionals get a wave of procrastinators coming in to file at the last minute, so if that sounds like you, they have some tips to make the process as painless as possible.

The first tip they offer is: if you're not going be able to do your full filing in the next week, at the very least, file an extension. It could save you a fine when you do file.

"It's not a delay to pay," H&R Block tax preparer Dena Wiberg said. "It's just an extension to file your return. You still have to pay your taxes and you still will have a penalty for not paying, but at least you won't have a penalty for not filing."

And if you don't owe the IRS anything, there's no penalty for filing that extension at all.

If you're still planning on filing by tax day, don't forget your W-2s, income statements, mortgage information, property taxes, vehicle registrations, ID, and social security numbers for yourself and any dependents you're claiming.

And as always, be careful who you trust. Verify that your tax preparer is licensed and be aware that people might call you trying to scam you out of your refund.

"The IRS will never call you," Wiberg said. "Regardless of whether you give them your phone number or not, the IRS will never call you, so never give anybody who claims they're the IRS money over the phone."

For a link to file an extension, click here.