The following is a cleaned-up version of my personal notes on how to create characters. Any discussions or suggestions of things I missed are welcomed.
Why think about character construction?
No two authors create characters the same way. Often characters are created intuitively, seemingly popping into our heads fully-formed. Sometimes they may be based on real people, either whole or as an amalgamation of several individuals.
But other times, an author may be held back from creating great stories by their inability to imagine new characters. This is seen most often when an author falls into the trap of creating a cast of characters who are all essentially the same person with different ages, genders, races, etc. Other times, an author may have a “stock set” of characters that they deploy for every story, and as a result every story they write is at heart just a copy of the previous one (although some authors have actually made lucrative careers doing this).
The Metanautics Department 