Military records and artifacts. This can include disability records, discharge records, National Guard records, pension records, selective service records, service medals or ribbons, sword or firearms, uniform.
Photographs. Photographs are great resource because you able to see clues such as branch of service, unit numbers, specific war or time of service, service ribbons and medals, rank, patches and pins related to skills and training. Photographs exist from as early as the Civil War.
Writings. As you research ancestor writings (e.g., post cards, letters, notes) look carefully at the time periods covering the various wars and conflicts. These communications are among the most saved and treasured in families. In our family we have the WWI letters between grandpa and grandma which share their inner most thoughts of being parted, activities, experiences, hopes and dreams. Look at clues such as post marks, stamps, inscriptions on post cards to see if they will give you any indications of where to look for information/records.
Scrapbooks and momentous. Look for collections of artifacts that include scrapbooks that are often organized by topic or timeline. I found a family trunk that was loaded with military images, letters, newspapers, postcards and much more from a WW I soldier.
Journals, written and oral family histories. Check to see if journals exist for family members. Has any member of your family written their memoirs about their military service? Is there a an oral history or written history related to military service. I’ve been fortunate to record the military experiences of my dad and his brothers for WWII and Korean War.
Newspapers. Take the time to search microfilm or online collections of newspapers from the hometown of where family lived during the times of War/conflicts as well as newspapers published for the soldiers. The newspapers were filled with stories about soldiers such as enlistments, graduations, letters from the front being published, promotions, images and deaths. Search every issue carefully; most stories about soldiers were on the front page of hometown papers. In our family we have articles showing grandpas enlistment in WWI and series of articles about an uncle in WWII 1) June of 1943 his plane was shot down in WWII and was missing in action 2) July of 1943 he is in a prisoner of war in Germany and 3) April 1945 he is freed. Your best chance of finding articles will be from 1890’s forward.
Death event records. As I have search for death event records, I have been able to identify references that have helped me research military records. For example, obituaries will often mention branch of military service and related details. Headstones can mention service and rank or even have markers related to branch of service.