Dan,
The key is to know the Rules or what I call the The Facts (Truth) About Tax Sale Investing. You have to know the rules (laws) for the State of interest to you, then understand How to Invest in that state respectively. Some states for example offer Investors an opportunity to Earn Interest on the Liens/Deeds that are purchased. A Tax Lien is usually subject to redemption period--during which the Investor earns interest on his/her money. A Tax Deed is also sometimes subject to a redemption period, depending on the State. Georgia, for example, offers Tax (Sheriff) Deeds, but subject to a 1 year and 45 day redemption period. On the other hand, some states offer Tax Deeds--with no redemption period at all (e.g., Hawaii, New Mexico, and several-several others). Once you determine a State that interest you, learn the rules for that State, know whether it is a Tax Lien State/County or Tax Deed State/county, map-out when the Sales are conducted, get an idea from the Tax Collector of the number of properties offered, redeemed, etc.---just call them for that and ask questions. You may also (which is a good idea) attend the sale to get to know who the players are before you Invest (Learn as much as you can first before you Invest). Be Patient with it and Have fun! Making Money (to me) should be fun---not stressful---so do do not lose your confidence--ever! Have Fun! Learn the Game and Make Money and Play to Win!
Before you Invest in a Property (RESEARCH) it to determine the Property Type, Its' Assessed Value and its' potential Market Value, Location/Area and know the likelihood of you owning it IF that is your goal. Don't be fooled---many properties are redeemed, but there are some states/counties in which you CAN actually Buy Properties "FREE & CLEAR". THE KEY: RESEARCH--RESEARCH. I have done a great deal of this and have found out about SALES that many people may not know even exist. For example, some states offer Tax Sale Properties "OTC"--Over the Counter, meaning you can buy them without attending the Sale. Some say these are left-over properties that may not have any value. Well that really depends on where you want to start financially. It is not at all a bad idea to buy one (A Tax Deed Property) to get a feel for how the Process work. Always buy direct from the County in this case---before you dive into the world of Buying from Third Parties or Individuals. As always, Buyer-Beware" is still the golden rule, but know that you CAN really do well.
Finally, EXPECT TO SUCCEED AT IT! RESEARCH AND YOU WILL BE BLESSED!
Much Success to you, MoneyMakers