My thoughts on histories: The place I'm at has them mandatory for approval, so I am biased in that respect, but I have found them to be really helpful. Even if some of them are vague. Come to think of it, all but 1 of my characters I've played has had relatively 'normal' backgrounds for their species. In other words, not insanely rich, no 'family got all killed' scenarios.

The quote I think that fits 'master plans' for a character goes to some military related phrase (sorry if I get this wrong, please correct me on it if it is): No battle plan survives first contact with the enemly. In other words, if there is a plan for a character, I do not expect it to come out like I plan. Instead, one of my favorite development and RP things to do is have goals for my characters and reach them.

I notice several have answered that their characters have been developed some more... but how do you do it? Myself it happens to be influenced by those other characters about, the first ones having the most effect normally.