I recently did a short story, where the main character (a little boy) shared parts of his backstory with a newfound friend, in kind of a get-to-know-you/sharing moment that worked pretty well in that particular case. I've also used the flashback/remembering method in other stories because it fit that character. I'm currently struggling with implementing the backstory in my NaNo story, as well as another story I've been brainstorming for some time. I don't think there is any "one size fits all" way to do it. To me, it depends on the character and the story. Just my take on it thought.