“Well” is the one I see most. “Yeah” runs a close second.
Get rid of them.
Don’t have words at the start of a piece of dialogue that are just you, revving up your motor before you get to the main event. Get to the juicy stuff with no wasteful prologue.
Don’t have someone say “Are you eligible for parole, Rocco?”
Followed by, “Yeah. You bet. In ten days.”
That’s fine for first draft, but then you trim to “In ten days.”
Or something far, far better than that. You’re the writer.