I am going through the Children's Writer's & Illustrator's Market to find publishers and agents to consider for my picture books. Then I'm checking each one out to find those who match my style of books. Then I'm researching each one to determine their absolute compatibility. This is time consuming, but will save me from embarrassing submissions to publisher and/or agents that have nothing in common with my books. This thorough search also helps me help the publisher and agents so they don't have to unnecessarily read my stuff when they're all wrong for me in the first place.
As promised, I'll keep you updated when I submit. I've found many to consider and am slowly weeding out those that are not a good fit.