I've been reading Foucault and having difficulties understanding how to employ his "genealogy" technique in uncovering historical concepts. Like, how do we actually know the certain moments/episodes that will have its outcome in the future?
I think (maybe?) the best approach to understand Foucault genealogy is to read studies employing such technique... so can I ask for bibliographical recommendation on it?
Well, firstly I would suggest also posting this to /r/askphilosophy, as Foucault is more considered one of those than one of these, though there seem to be more "professionals" in this sub. /r/criticaltheory and /r/historyofideas are also quite big on Foucault, but small and not very active.
I'm probably kicking in open doors, but the best place to start is Foucault himself, have you read Discipline and Punishment, or really most of his later work?
I would highly recommend David Halperin's How to do the History of Homosexuality, particularly the essays "Forgetting Foucault" and "Historicizing the Subject of Desire." All the essays are fascinating and if you've read The History of Sexuality vol. 1 then you'll have a really good basis for understanding what Halperin is saying even if you aren't a Classicist like he is; unlike Foucault who focused mainly on sexuality in the 18th-20th century, all of Halperin's examples are pre-modern and mainly from Antiquity.
Eve Kosofsky Sedgwick, The Epistemology of the Closet. Really dense....but excellent and painstaking work that's inline with Foucault's genealogy.
Elaine Scarry's Body in Pain is also coming to mind, for some reason. I can't say that she specifically mentions Foucault...but her analysis of pain and its representation really seems to draw on Foucault's methodology.