I'm not a big fan of flashbacks. I've used them before, but I usually prefer to just tell the story in order and find other ways to work in the backstory. When I do use flashbacks, I put them in italics and separate them from the rest of the narrative with an extra line of space. Like a lot of you have said, it drives me nuts when I see flashbacks labeled "~*~FLASHBACK~*~". I prefer to think that my writing can stand on its own and that my readers are intelligent enough to infer that it's a flashback LOL.
As for point of view, most of my stories are written in third person limited point of view from one main character's perspective. Some of them, like By My Side, Secrets of the Heart, and Song for the Undead, change which character the POV is limited to each chapter or scene. In BMS, I didn't do anything special to signal that change because it was only between two characters. In Secrets, as well as Curtain Call, I label the chapter title with which character's perspective it shows. In Undead, we start each chapter with a journal entry written by that character (in first person), then go to the third person narrative showing that character's perspective. Just like with the flashback thing, I'm not a fan of labeling each scene with "~*~Brian's POV~*~" and "~*~Nick's POV~*~" etc. Especially when it happens multiple times in the same chapter. Stop switching POVs already!! LOL