Property values have fallen significantly in most metro Atlanta counties, so governments have, in many cases, raised millage rates to compensate for the drop in revenue. But if you don't get your assessment lowered, you end up paying more than your fair share of the property tax burden.

What can you do about it? Plenty!

Starting Jan. 1, you can file a property tax return with your county tax assessor. In it, you will be stating your estimate of your property value as of Jan. 1, 2012. That estimate needs to reasonable and justifiable, or it will be rejected by both the assessor and the board of equalization.

In a nutshell, you are trying to make the case that, due to similar homes that have sold during the past 12 months, the value of your home on Jan. 1, 2012, has dropped from last year's valuation.

Here are the steps you should be taking in the next few weeks:

1. Collect sales data.

You need to get a list of all actual sales (not listings) in your neighborhood that have occurred during calendar year 2011, because those sales will be an indicator of your home's value. Get the list from the Internet (try zillow.com or trulia.com) and verify it with realty agents who are active in the area. The closer physically (both location and features) the sold homes are to yours, the better.

2. Compare sold homes to yours.

The most important data are location, age, square footage, and the bedroom and bath count. Also, try to determine the condition of the property. Has it been completely remodeled? While other factors are noted in a formal appraisal, they generally are given lesser consideration in valuation.

Foreclosure auction sales are not considered because they are not "arm's length transactions," but bank resales (where the lender sells to someone else) do count, and that can help you very much.

If a bank resale was at a particularly low price, make sure you stress it in your comparisons. While I personally consider these to be "distress sales," the appraisal community does not, and they write the rules.

For the purpose of property taxation, you want your home to be worth as little as possible, and foreclosure resales can have a devastating effect on value. Find them and use them to your advantage.

3. Visit the houses.

See each house from the street, take photos from your car, and compare each home to yours. If you can reach the listing or selling agent, call that person and ask questions about details and condition of the interior. Then assemble all the comparable sales data on your desk.

4. Estimate the value of your home.

By making adjustments for sales that were less similar to your home, you should be able to come up with a ballpark guess as to what your home will be worth on Jan. 1, 2012.

You can ask a real estate agent who is familiar with your neighborhood to help you, but be prepared to pay for that person's services, or at least offer to do so.

While agents are not trained as appraisers, they are very familiar with sales activity and often have a keen eye as to values. Make sure your estimate of value is justifiable and reasonable.

5. Submit your property tax return.

Using Georgia form PT-50R (available at money99.com), submit your estimate of your home's value and include a one-page summary of your comparable sales and why you feel your home's value has dropped. Then mail the form to your tax commissioner by certified mail, return receipt requested, and keep a copy along with your postage receipt.

Due to the huge number of property owners asking for a review of their value, the assessors offices are being buried in paperwork, so don't trust regular mail. And if you haven't received your return receipt by the end of January, either send it again or deliver it in person and get a receipt. Misplaced paperwork is not unusual.

You can do this anytime between Jan. 1 and April 1, 2012. The sooner you submit your return, the sooner you may see a reduction in your property tax bill for 2012. But whatever you do, don't miss this opportunity to lower your taxes.

John Adams is an author, broadcaster and investor. He answers real estate questions submitted through his website and in this column. For more real estate information or to make a comment, visit www.money99.com.