This question is about responsible historiography. History as written by winners tends to devalue and misrepresent the experiences of subordinate groups (see Textbooks: Zinn People’s History; Labour: Engels German Peasants War, Hammond & Hammond Labourer [Series], Thompson Making ; Gender: Engels Family, Private Property, James & Dalla Costa Power of Women; Race: CLR James Black Jacobins).
Many Anglo immigrants to California described its natives as lazy and dirty. If this was an attempt at ethnography it backfired, telling us more about the authors than their subjects. This example is extreme, but dominant discourses that reflect majority outlooks and deploy otherness are hard for authors from dominant groups to escape.
Those authors are prone to uphold dominant narratives and "punch down" at other groups even by accident. The result is that writing about other groups can be considered dubious. An article about fiction writing asked "Are White Authors Not Allowed To Tell Stories Involving Black Characters?", while Richard Griswold de Castillo called inadequate Mexican-American history written by others historia chicanesca (Chicanoesque history). Minority groups have sought to tell their own stories instead of having stories imposed on them.
Despite these concerns, privileged historians do often write in good faith about disempowered minorities and the oppressed. Their work does not satisfy subjects' understandable desire that their history be written by their own people. For this reason I suspect that historiographers have already spilled ink on the matter of writing about such groups without adding to the burden they already face.
Are there recommended practices in this area? I will speculate that deconstruction of known narratives and meticulous history from below could be elements of such a strategy. Hopefully something more systematized is out there.