All characters come from people I know, but after the initial inspiration, I tend to modify the characters so they fit with the story.
The inspiration for my novels comes from the depths of a creative well, based on asking myself questions over and over. I try to write something different each time I sit down to write; I try to surprise the readers.
Inspiration can come from anywhere - an image, a comment, something that's happened to me or someone I know. It's hard to know exactly.
While I find inspiration in real life, the actual stories are, thankfully, works of fiction - which, given the considerable turmoil in my character's lives, is probably a good thing!