We have talked about filing systems before, but I neglected to mention the importance of having a special group of files called "Locality Files." The use of locality files is advocated by the Family History Library (FHL) in Salt Lake City, Utah and it will certainly help you with your research.
You should have a separate file for every state and for every county you do research in. They should be labeled something like this:
Georgia
GA -- Columbia Co
GA -- Lincoln Co
GA -- McDuffie Co
GA -- Richmond Co
Mississippi
MS -- Forrest Co
MS -- Lamar Co
MS -- Marion Co
MS -- Perry Co
North Carolina
South Carolina
SC -- Aiken Co
SC -- Barnwell Co
SC -- Edgefield Co
In the individual county files you need to have a note that lists what year the county was formed and from what other counties it was formed from. You might also include county maps showing the boundary changes over the years. This will help you when you are trying to figure out which county a particular document will be located in based on the date the document was written. Other useful things to include would be a written history of the county and the addresses and phone numbers of the courthouse, public library and health department/vital statistics office. You can also include marriage records, index of wills, cemetery surveys, military unit rosters etc.
The FHL publishes research guides, research outlines and statewide indices and collections for every state. These guides are a must. File these in your state folders. They will save you a lot of time when you are trying to figure out what resources are available for that state as well as where those resources are located. Some of these guides are available in print, and you can order them from the FHL by calling 1-800-537-5971. They only cost $2.50 each. The rest of the publications are available online for free at www.familysearch.org. Click "Site Map" then "Family History Library Publications," and you will see a list their publications. All you need to do is print them out and put them in your folders. Some other things you might want to include is a list of when that state mandated birth and death certificates and information about military units from that state including when and where they were formed.
I have my locality files in hanging file folders, and these folders are labeled just like I have already listed. I also have a file labeled United States which contains two different research guides for general military research. I have a file for Germany which has a research guide, a German wordlist of genealogical terms, a handwriting guide for the old German script used prior to WWII and a letter writing guide for correspondence done in German. These are all available from the FHL.
Over time, you will be expanding your research over many counties and states. It is an easy task to keep all of this information right at your fingertips. I encourage you to invest a little time setting up your own locality files.