Names are very important, because they give character without ever writing another word. They also convey the tone of the piece; if your names are a parody or comedic in some way, it lends a lighter tone to the piece you are writing. Finding the perfect name for a character, especially a villain, can take a lot of time and thought. I keep a list of interesting names in my phone/notebook which might come in handy some day. I have been known to change a character’s name during the last draft of a novel, because I have finally found the perfect name.
However, it must be said, that just like people, character can grow into their name. This can effect your entire story/novel if you decide to change a character name at a later date (not recommended).
Obviously I need to knew basic details about my characters: what they look like, what they wear, how they talk, mannerisms, habits, etc. However, when it come to character flaws, I try to provide some back story to explain why they are the way they are or what caused a certain character trait.
Knowing why, helps to paint the character as a more rounded person. They aren’t just a gambler because we need a villain who gambles, they have become a gambler through a certain set of situations/upbringing/etc. If you can come up with three or four little stories/situations that illustrate this character trait, it will add more depth to your charactert – you don’t need to produce these in detail, because you will fill out the details to fit the script, but they are useful to have in reserve.