Usually, if you haven't filed your federal tax return by this time, you're either a procrastinator or avoiding paying Uncle Sam the money you owe.

But this season, more filers than usual are dragging their feet. The number of returns submitted by late March was down by more than 2 million compared with a year earlier, according to the latest IRS figures.

"It has to be tied to the economy," says Bob Meighan, vice president at TurboTax, maker of the popular tax preparation software.

People who lost jobs during this recession might have incomes so low they don't have to file, he says. Or those who are struggling financially might still owe taxes but are putting off filing while trying to figure out how to pay the tab.

Or it could be that taxpayers are overwhelmed by all the tax changes this season - H&R; Block counts nearly 300 - and they need more time.

Whatever the reason, the clock is ticking, and taxpayers have until Thursday to get returns in - or to ask for more time to file.

Even at this late stage, you still have time to take advantage of a couple of maneuvers to lower your 2009 income and your tax bill. At the same time, you need to make sure as you rush to meet the deadline that you don't overlook the new deductions and credits - as well as some of the old ones.

"If your income declined because you were laid off or your investments did poorly, you may be eligible for tax deductions and credits that you were not eligible for in the past because your income was too high," says Bob D. Scharin, senior tax analyst at Thomson Reuters' Tax & Accounting.

Using tax software can alert you to deductions and credits and help reduce math errors. Taxpayers with income of up to $57,000 can file returns electronically for free under Free File at www.irs.gov.

Here are some last-minute tips:

Fund tax-sheltered accountsYou have until April 15 to put up to $5,000 - or $6,000 if 50 or older - into an individual retirement account for 2009 and possibly get a deduction.If you don't have a retirement plan at work, you can deduct all contributions to a traditional IRA, no matter what your income is.

Those covered by a workplace plan can deduct some or all contributions to a regular IRA if income is under $65,000 for singles and $109,000 for joint filers. And if your spouse has a retirement plan at work but you don't, you can deduct all or some of your contributions provided your household income is less than $176,000.

(You also can contribute to a Roth IRA if you meet certain income limits, but you won't get a tax deduction upfront.)

Thursday also is the deadline to fund your health savings account for 2009. Health savings accounts are combined with high-deductible health plans. Tax-free money is put into the account where it can earn interest and later be withdrawn free of tax to pay medical expenses.

If you haven't already funded your health account through payroll deductions, you can do so now and deduct the contribution on your tax return, says Elaine Smith, an enrolled agent with H&R; Block. For 2009, individuals can contribute up to $3,000 into the account; families can put away as much as $5,950.

Buy a houseIt's not too late to buy a house and get a homebuyer credit. Buyers who haven't owned a house during the past three years could qualify for a first-time homebuyer credit of up to $8,000.

As of Nov. 7, homeowners who have lived in their houses for five straight years during the previous eight years can get a credit of up to $6,500 if they buy a new principal residence. "You don't have to have sold your old home," Smith says.

To claim either credit, the new house must be under contract by the end of this month and the deal must close by the end of June. For purchases that don't close before the tax deadline, filers can ask for an extension of time to submit a return or amend their 2009 return later, says IRS spokesman Jim Dupree.

You must file a paper return to claim the credit and provide documents to show that you bought the house and, if claiming the $6,500, that you lived in the old house for the required five years.

Bigger standard deductionA homeowner who doesn't itemize can get a larger standard deduction by also deducting up to $500 - $1,000 for joint filers - for property taxes paid on a principal residence last year. This is targeted mainly at retirees who have paid off their mortgage, Meighan says.

Making Work PayThis credit was designed to put up to $400 extra into the paychecks of single workers last year and $800 for married couples by reducing tax withholdings. Some got the full amount already; others didn't. Either way, you need to file the new Schedule M to claim the credit.

Schedule M has confused many filers. The IRS says its examiners will be on the lookout to make sure workers get their rightful credit - even if they didn't file Schedule M - and will correct returns.

Breaks for the unemployedYou don't have to pay income tax on the first $2,400 of unemployment benefits received last year.

Also, if you are looking for employment in the same field, you may be able to deduct job search expenses. Money spent on resumes, travel to interviews or job counseling that exceeds 2 percent of adjusted gross income can be deducted as a miscellaneous expense on itemized returns, Scharin says.

Helping HaitiCharitable donations to Haiti relief efforts following January's earthquake can be deducted on your 2009 itemized return, provided the gift was made before March 1. (Donations to Chile following the earthquake there in late February will have to be deducted next tax season.)

Higher education creditThe new American Opportunity Tax Credit is worth up to $2,500 of the cost of tuition, fees and course materials for higher education per student. It can be claimed in any of the first four years of school. Better yet, the credit is partially refundable, meaning if you don't owe any taxes you could get up to $1,000 back as a refund.

A full or partial credit is available to singles with income of up to $90,000 and joint filers making up to $180,000.

Energy creditsHomeowners can get a credit of up to $1,500 for adding insulation and energy efficient windows, doors and heaters to their main residence. Also, you can get a credit worth 30 percent of the cost of big-ticket items such as solar water heaters and geothermal heat pumps, and there's no dollar cap. Check energystar.gov to find which items qualify.

Car tax breakDeduct the sales tax paid on the first $49,500 spent on a new car, motorcycle or mobile home purchased last year between Feb 17 and Dec. 31. This deduction begins disappearing once income reaches $125,000 for singles and $250,000 for joint filers.

Need more time? Get an extra six months to submit a return by filing Form 4868. As many as 12 million filers do so each year, Meighan says. "I'm one of them," he says. "Who has time for that right now?"

You get more time to file your paperwork, but you must still pay your anticipated tax bill by April 15th.

Don't have the money to pay? The IRS offers payment plans and recently announced it would be more flexible about settling tax debts for less than owed.

You also can pay by credit card, but avoid this if you can, says Bill Hardekopf, chief executive of LowCards.com.

Companies processing payments for the IRS charge fees of 1.95 percent to 3.93 percent of your tax bill. On a $3,000 tax bill, that could run as high as $117.90.

And if you can't afford to pay off your credit card bill when it comes due, you will be paying interest on top of that, Hardekopf says. "Some have [interest rates] that are over 20 percent. It's a significant penalty," he says.

Filers could be better off with an IRS payment plan or taking out a personal loan at a bank or credit union, he says.