Listen to Your Characters
Rather than what I suspect is the standard approach, that of drafting the background and incidental details all at once, and typically before even the first game session has taken place, what I'm now envisioning is a process where the character background grows organically over time.
In this new approach, players should at the time of the first game session, know the basics, what's readily apparent from their character sheets, but details beyond that can be left somewhat vague and filled in over time. This could be something as minor as character details, or something as major as character motivations and goals.
In the past I might have a character background that states that "Johnny" is the oldest of 5 siblings. But in this new approach, I might not know for sure if Johnny has has sibs, until a role playing moment comes along where having a sib, or being an only child has some emotional impact. Maybe Johnny did have an older brother who died at a young age, so when Johnny and the group are investigating a series of child murders, the events impact him pretty hard.
Maybe my character at first seems to be adventuring as a way to earn money, but later reveals that he seeks revenge on the man that that killed his parents, who just so happens to be the Big Bad of the current adventure. Plot twists like this are a common staple of literature and TV.
In fact, soap operas offer outrageous examples of "flexible" characters -- where a character is first introduced as a nice quaint doctor, then revealed to be the evil-twin thought to be dead brother who is actually a rogue Soviet assassin. And we think of fantasy literature as highly creative...
By keeping the character background flexible, new plots and dimensions can be added organically from the events in the game so characters and be integrated in ways that can be both interesting for the player as well as the DM.
Now this type of approach does have some caveats. First, all the players and DM have to have a trust one another. It can be easy for some players to monopolize the role playing elements by creating a number of different hooks while other characters don't have much of connection. What you want to avoid is a party where one player is Crocket and everyone else is Tubbs, or worse, a group where one is Drizzt and everyone else is, well, everyone else!
But that said, with the right group of people, this flexible approach can easily open more role playing opportunities, and provide adventures with more emotional impact.
