That's what Ken Follett does. Follett, author of thrillers such as Eye of the Needle, Pillars of the Earth and World Without End, was interviewed along with David Morrell (whose most famous character, John Rambo, debuted in Morrell's 1972 novel First Blood) by Writer's Digest. Both authors share a wealth of insights into the writing process, the value of agents, and other topics.
Be a first-rate version of yourself and not a second rate version of another writer.
Every character must have a thrust, something he or she is yearning for, trying to achieve. Otherwise, no matter how interesting the character is, there's no story, no forward momentum.
I have a lot of reasons to think that reality is not a friendly neighborhood. And the stories that I tell distract me, and if I do the job right they distract people from the things that are happening to them that they wish had never happened.
It’s the ability to make you think again about what you’ve already written that is so useful. Somebody who can say, this scene lacks something, or this character.
— Follett, on what to look for in an agent
Even if you don't write thrillers, the advice Morrell and Follett offer is invaluable. The entire interview is long, but well worth your time.