Nothing cripples a writer faster than not feeling a kinship/having knowledge of, their characters. There is no quicker death to a story than the lack of a character that, in some way, makes his or herself memorable to the audience.
I fight with my character development. I think I've already stated that. It is a bane to any writer not to have good characters. I try to control it by keeping separate files of thoughts and beliefs about my characters as well as rough sketches of what they look like, what drives them, etc.
I gotta tell you, it can be difficult. I don't always know right away what drives a specific character. Why do they dislike this person? What makes this one so happy? What makes this other so angry? But, its a handy tool that I've slowly come to find is indispensable as far as a novel goes. Not only do I have a separate area to speculate on my character's role in the store, it keeps a running record of various physical attributes. Sometimes, when you get deep into a novel that has several significant characters, it isn't always easy to remember this one's height or that one's eye color. You wouldn't think so, but its true. I get so enmeshed in the story that those little details leave my brain. I suppose it doesn't help that I'm attempting to write two books at once, either.
I don't think the children's novel is going to be too long. That's good, though, I think. Who wants a "War and Peace" of children's novels? I think that it will be a short area of adventures for my character, but hopefully complete, just the same. I hate a rush job.
And, is anyone out there? Can I get a "hey" or "booyah" or something? Sheesh people. If I want to just talk to myself, I can do that without keeping physical evidence of my lack of sanity! 8)