As you thumb through the mail one day, an unassuming letter catches your eye. Return address: The IRS. You nervously tear open the envelope and your worst fears are confirmed: The IRS has chosen your return for a correspondence audit. How do you beat an IRS audit?

If you bought a new car in 2009, get out your calculator: Your tax deduction choices are more complicated this year. Here’s why:

Form 1040 isn’t the only IRS form that’s been updated for 2009 tax returns. Here are several major changes on the accompanying Schedule A (Itemized Deductions), Schedule B (Interest and Ordinary Dividends) and Schedule D (Capital Gains and Losses).

Before you hunker down to fill out your 2009 tax return, be aware of all the changes on the Form 1040 this year. Here’s a summary:

You’re embarking on a big project and you want to do it right. So you draft a detailed plan. Just make sure it pays off.

Due to the economic slowdown, the IRS expects more taxpayers to file early and claim their refunds sooner. Electronic filing is the quickest way to obtain a refund. Paper returns take four to six weeks to process. In contrast, e-filers can generally expect to receive refunds within 10 days.

There’s nothing humdrum about the Form 1040 you’re about to file with Uncle Sam. Thanks mainly to the economic stimulus law passed last year—the American Recovery and Reinvestment Act—the ’09 return is chock-full of tax breaks for the well-informed. Here are 10 tax moves to wake up to this year:

Are your kids nearing the time to enter college? If you’re like many parents, you may not have saved enough to finance the higher education of your offspring. Now it’s too late to benefit to any significant degree from a Section 529 plan or other college savings vehicle. Don’t panic. As the clock ticks down, you may be able to turn to other sources, without paying a small fortune in taxes.

South Dakota has replaced Wyoming as the state with the best “business climate,” while New Jersey remains the worst in the annual State Business Tax Climate Index (SBTCI) conducted by the Tax Foundation, an independent tax advocacy group. The SBTCI ranks states based on the taxes that matter most to businesses and business investment: corporate tax, individual income tax, sales tax, unemployment tax and property tax.

Q. My son was laid off from his job in April 2009. Does he still benefit from the new extension for COBRA subsidies?

President Obama’s State of the Union address on Jan. 27 outlined a broad agenda of tax provisions that are intended to breathe new life into the economy. The overall idea is familiar: take more from taxpayers at one end of the financial spectrum and distribute it to some at the other end, using a series a tax provisions. Here are some highlights of Obama’s proposed changes:

Q. I bought a new car costing $60,000 in 2009. Can I deduct the sales tax for the new vehicle purchase plus an amount for the optional sales tax deduction?

Is someone in your family planning to adopt a child? It can be costly and time-consuming—not to mention the emotional roller coaster. Strategy: Recoup some expenses through the adoption tax credit, which reduces your tax bill on a dollar-for-dollar basis. Although it phases out for high-income taxpayers, many parents—especially younger ones—will benefit from at least a partial credit.

While many 401(k) plan participants jumped ship following the stock market’s plummet in 2008, some have slowly been returning to the fold. Strategy for business owners: Add an “automatic enrollment feature” to your 401(k). This will encourage those employees still on the bubble to participate in the plan. In turn, you may be able to stockpile more money for your own retirement.

Cary and Brenda Jensen worked for the Lodge at Mount Snow, placing ads and organizing bus tours for senior citizens groups. After six years, the Jensens quit to open ...

A new law enacted late last year extends the “temporary” FUTA surtax for 18 more months. Undoubtedly, we haven’t seen the last FUTA surtax extension from Congress. But with a few smart moves, you can lower your state unemployment tax rate. This will save you money over the long run—whether or not the federal surtax is extended again and again. Here are six ways to keep unemployment tax costs under control:

Q. I’m selling my house where I’ve claimed home office deductions in the past but not depreciation. Will my home sale exclusion be reduced?

Thanks to a new law change, longtime homeowners can now get a piece of the homebuyer credit pie. But you have to move fast if you plan to buy a new home. To qualify, you must complete the purchase before May 1, 2010. If you secure a binding contract before May 1, you have until June 30, 2010, to finalize the sale. Best of all, you can claim the credit on your 2009 return—even if you buy the home in 2010.

Q. We’ve been using a SARSEP for our business. With the new rules for DB(k)s in place, are these still valid?

The “Worker, Homeownership and Business Assistance Act” includes a powerful tax-saver for struggling business owners. It extends and expands the earlier Stimulus Act’s tax break for net operating losses. Strategy: Let the tax law do double duty. If you qualify, you can take advantage of the enhanced NOL carryback rules for both 2008 and 2009. A business that carries back an NOL to a profitable tax year is entitled to a quick tax refund from the IRS.

The end of the year came and went without formal approval of the “Tax Extenders Act of 2009.” But once enacted, the new law would retroactively extend a bunch of key tax provisions that expired after 2009. Generally, it will preserve these tax benefits for one more year. Here are the main tax winners for individuals and businesses:

Maybe you’re not planning to move anytime soon despite the new homebuyer credit. As long as you’re staying put, you might decide to invest some money into the house. But you generally receive no current tax benefit from home improvements. Strategy: Make home improvements needed for medical reasons. If certain requirements are met, you can deduct a portion of the cost this year.

You may not realize it, but many small business owners adopt war principles to lead their companies to higher profits. Think about it:

Q. I transferred mutual fund shares worth $3,000 to my niece for her graduation. My basis was $2,500. If she sells the shares for $2,200, can she deduct the full loss?

Besides the new DB(k) plan option, small business owners can choose from a wide variety of qualified retirement plans, subject to a bewildering array of rules. Now the IRS wants to help you chart your course. It has launched a new online resource called the Retirement Plans Navigator.