I have the most wonderful illustration rep out there, Maggie Byer-Sprinzeles. She is the perfect rep--for me.
She may not be the perfect rep for you. Every illustration representative is going to have his or her own way of working. It may mesh with the way you work, it may not.
Where to seek and even whether to seek representation requires some serious reflection on your own working style. If your favorite part of illustration is the marketing, you may not even want someone to represent you.
If you decide you DO want a representative, you'll first need to do some homework. Look at the reps that handle children's illustrators. Really examine the work of the artists each one reps. Does your work fit in with this agent's portfolio of artists? If you do wacky whimsical work and this agent only seems to rep realistic artists, this one may not be right for you.
Then contact those with whom you think you're a good fit. They may have guidelines for submitting on their websites, otherwise, an email with links to your online portfolio is probably a good way to start the introductions.
Guess what...you may get a few rejections. It may not have anything to do with your work (it could be that they have a full roster, your style may not suit them or the clients they solicit, etc.).
Once you do get interest from an agent, here are a list of questions you might want to consider asking a potential rep:
1. What services do they provide?
2. How does the agent/artist/client relationship work? (I've heard of reps who always act as the middle-man between the illustrator and the art director. This wouldn't work for me at all, but if you're morbidly shy, this might be a working style you'll LOVE).
3. Is their contract for exclusive representation? If so, what does it
encompass (writing? illustration? licensing? all work or just children's
publishing?, etc.)? How long is the contract for? What are the steps to end the relationship?
4. Can you still promote yourself? Do you have to give a percentage of the money on deals you make yourself?
5. What about relationships you've already established?
6. What types of clients do they work with most (educational, trade books, mass market books, etc.)? If their answer to this isn't for the markets you're wanting to approach, then they probably aren't the right choice for you.
7. What do they require from you? Some reps require you to buy pages in illustration annuals, some do not. Some require you to send them new samples at specified times.
8. What do you have to pay? 50% of advertising? 60/40%? Mailings? 50% of printing of materials? Anything else?
9. Can you talk to some of their current artists? I have had several people call me about my rep after I've given my permission for them to call.
What it really boils down to, is what do YOU need and want from a rep?
Here are some other very helpful sites about children's illustration reps:
Good luck in your decision!