I often create pre-gen characters for one-shots and convention scenarios. The more I've done it, the more i've come to realize this is an art unto itself.
Since they are only going are probably only going to be used in 1 scenario by the player once (assuming one-shot or convention), they have to be "strong" enough to last the entire scenario, yet interesting enough for anyone to play.
I was curious if anyone has any particular way they create pre-gens or tips they would like to share. Or are there any little quirks you always give one of the PCs? For example, in all my scenarios, one of the PCs is always from Battle Creek, MI.