To whom are you writing? Libraries, archives, or government agencies have limited staff resources and cannot "do" genealogical research. However, staff can look up specific information, such as births, deaths, marriage, or census records. Private agencies (and many public ones) rely on volunteers who may have varying levels of expertise. Professional researchers make their living by locating and interpreting information.
Inquire about fees for research services before asking questions. Do not expect an institution or individual to provide research services for free because you ask for the reply to come via e-mail or fax. You are paying for the time, not just the copies.
Include your full postal service address so that researchers will know where to send any materials that are copied. Even in e-mail transactions, this can save a step. Also be sure to include your full name in e-mail queries.
Include a self-addressed, stamped envelope (SASE) for reply convenience. Some organizations or individuals will not respond without one.
Identify the type of record to be searched. No query should ask for "all" the information on a family from anyone except another individual who is known to have a file on the family. There are no universal indexes.
Request information about a specific person. When the information you have is incomplete (as in the case of a woman's maiden name which you would like to learn), try to provide as much information as you have which will help researchers determine if they have found the correct record.
Provide known spelling variations, especially if they differ greatly from the "standard" spelling. This will encourage researchers to look under those names as well.
The place where the event occurred is very important in shortening the search time. For example, at the CAC, vital records are organized by county and newspapers are organized by their community. Again, there are no universal indexes. If you don't know where an event took place, try locating the family in the federal census and start from there.
The date is also important in shortening the search time. This tells the researcher that an event with similar names at another date is not of interest. The more specific the date that can be provided, the better.
Sign your full name whether you are writing through the regular mail or e-mail.