Check to see if the library has a website. Most library websites provide the basic information associated with hours of operation.
Larger libraries, like the Library of Virginia, and state or country archives have an online catalog. Search the catalog before you go. I have usually been able to locate specific books, microfilm, papers, photographs, and so on that will be available for my specific research. Make sure you print out the details from your catalog search.
Check out the Library of Congress Card Catalog to determine what books have been published about the county or area you’re planning to visit so that you can look them up in the local library you’ll be visiting.
Write to or email the libraries that don’t have online information to find out about their genealogical collection, location such as floor or level, building, and hours of operation. Some collections in libraries can only be seen at specific times or may have special restrictions.
I have also found it helpful to call the library and talk with a librarian to see if there are staff researchers that can help if I have questions. Learn about the expertise of the staff. In some cases, I have planned to visit a library when the librarian with the expertise I needed was going to be working.
There may be local researchers who are available as volunteers and for hire who know the library and are willing to work with you to quickly get information you seek.
Make sure you make time to concentrate on using indexes, manuscript collections, unpublished records, rare books, photo¬graphs, and sources unique to the library or archives where you are researching before you get to the more distributed information that other facilities will have.
If the library doesn’t seem to have what you are looking for, make sure you ask the library for recommendations of where to go.
Also be aware of local traditions. One genealogist tells of an experience when they visited archives located in Glasgow, Scotland. When the genealogist arrived at the archives at the prearranged time, the primary archivist left for her daily two-hour tea and lunch break. The supporting staff was unable to assist the genealogist. Upon the archivist’s return, she was able to locate in a matter of minutes records of local cemeteries that the genealogist had been told by the staff did not exist.