When you contact an archive the first time, it is helpful to know how the materials are preserved in archives and how to search for a record. Before getting to the archive materials you should gather data about the matter of interest also from other places. After profound preliminary work on data-gathering it will be clear if there is any need to involve archive materials in the study and if it is needed, then which kind of finds one has to use.
This preliminary gathering of data should move from simple to more complicated. First one should ask background information from the people who have raised the subject or are well acquainted with it. In the case of the local history it might well be a schoolteacher or parents who can tell the first facts. If possible, one should talk with the people who have studied the issue earlier or read the research work written on the theme. Lots of useful information can be found in local or central libraries, in large and local museums etc. Often these institutions preserve chronicle materials, so-called school or village chronicles. If you have information that some local hobby-historian has been studying the theme you are interested in, then it is worth of trouble to search for his writings in regional newspapers too.
There is much useful information in the biographical books of reference and special lexicons:«Eesti kirjanduse biograafia» (The Biographical Lexicon of Estonian Literature), «Tartumaa talud» (Farmsteads in Tartu District), «Album Academicum», address and telephone books etc. should be mentioned here.
It is not possible to give an exhaustive survey of the main works on all the themes, librarians can give you a good advise here.
You can search for information also on the home pages of museums and in the electronic catalogues available in the Internet. The National Archives of Estonia is preserving materials for very different themes of studies, but much of these records are not in Estonian. Most of the older documents are handwritten in Gothic script. For that reason special knowledge may be needed if you want to use these materials.