From first time author's creations to characters created for NBC, Carls Jr., Van De Kamp foods, Atari, Comcast and a number of internationally known sport franchises here are some real personalities I've had the pleasure to help bring to life.
Once your character has been created, and approved, it's important to create a "model sheet" based on that character.
Traditionally model sheets are very important for animation as it "locks in" a character's appearence, so the multiple artists that may be needed to create an animated film know how to draw the same character in the same way.
I find it's very helpful to create a model sheet for characters appearing in books, which generally require multiple illustrations. It's a way for a client to know- and sign off on- how their character may appear from different points of view.