The question I'm asked the most is , what is the best form of promotion, what has worked best for you?
For me personally, different things at different times have worked. Referrals, packet mailings (showing several samples at one time), postcard mailings, conference networking.
By no means am I an authority on this , each illustrator finds what works best for them and I'm still experimenting/learning too. After trying several different methods, though, I've come to the conclusion that there are 2 really important factors. 1) BE SEEN 2)Whatever method you use, it MUST reflect professionalism.
I learned about promotion by studying the "Children's Writers & Illustrators Market" book. 
This comes out annually and has wonderful articles for illustrators (and writers) to help learn the ropes plus all the contact info for publishing houses. It's a MUST HAVE. This years edition has an article specifically geared to the topic of postcard mailings, I would highly recommend reading it.
Right now, I really enjoy using postcards for my promotion. You have to remember that Editors/AD's are busy and the postcard is immediate. You want to make life as easy as possible for an editor to get a feel of who you are and what you do. With the postcard, your work WILL be seen because an image isn't as easy to ignore as an envelope. If you go this route, though, it's crucial that you have a web presence. If an editor/AD likes what they see on your card, they can view your on line portfolio to see more of your work.
Editors are bombarded with submissions daily so it's important to "remind" them that you are alive and well , ready to work! My goal is to send out a postcard every three months and I send out a fresh image that they haven't seen before.
What to put on your postcard?
Since you are only showing one image with a postcard it needs to be memorable. Showing interaction is key in children's illustration. Children, animals, adults etc. Engage the viewer, make it feel like you are looking in on "their" world.
The backside , I usually put another little piece of spot art and my contact information...maybe a blurb about the medium I use or a partial client list.
I used to use my trusty computer and printer to create my postcards but lately I've been using postcard services on line. If you're interested, go to my sidebar and click on "Speaking of postcards" and you'll find links to check out there.
Paige of "Fox in Sox" wrote a great post about promotion here.
Holli of "A girl who creates" writes candidly of her experience with promoting herself here.
Art Rep , Chris Tugeau of "Catugeau" offers wonderful insight on how to represent yourself well here.
Katie Davis (Thanks Janee!)
Postcard mailings aren't the only route to go, it's part of your illustrator arsenal.
Get your work out there and start experimenting to see what works for you.
Remember that the most important thing is getting really good at what YOU do as far as style. Your art will speak for itself no matter which form of promotion you use.
Good luck!
Ah, Roz, you wrote your blog just for me!!! You are such a wealth of information. Thanks for putting all this on your site. I love it.
-heather
Posted by: humblebee | February 16, 2005 at 03:35 PM
Oh wow, Roz, this is so neat!
If I should do it one fine day and become an Illustrator I will come over and give you a great bear hug, can I do that?! ;-)
I've been thinking about it and thinking and procrastinating and procrastinating a little more...(sigh), me an Illustrator? Nah, that's what other people do, but not me...(sigh).
I'm still trying to figure out which direction excactly my talents are leading me.
Thanks for putting all this on your site, I just need a little push maybe...(ha! Where is my pushangel when I need him or her?!) and then my path will become clearer and clearer. :-D
I'm heading into the right direction, that much I know, just need to get the steering more precise.
Posted by: Tine | February 17, 2005 at 07:26 AM
Bear hugs are always welcomed ,thanks you guys.
I think we're all in the same boat trying to find our way.
You are very talented , Tine , I have no doubt YOUR way is going to find you!
Posted by: roz | February 17, 2005 at 08:33 AM
Thanks, Roz, I am keeping my eyes and ears wide open, believe me... :-D
Posted by: Tine | February 17, 2005 at 08:45 AM
I've been imptaiently waiting for my copy of the "Market" book to arrive; it's finally here! I've been voraciously reading it, and am already making several "notes to self." Thank you for being such a great resource to those of us who are taking our first steps towards realizing a dream. I love looking at your website. Not only are you uniquely creative, you're also extremely savvy. Lucky for us you're so willing to share that intelligence!
Posted by: Maeflower | February 19, 2005 at 02:20 PM
Oops, here we go. This is the REAL link to my website. Sorry!
Posted by: Maeflower | February 19, 2005 at 02:21 PM
Oh, I'm so glad that you are finding it helpful, I appreciate you taking the time to let me know.
I'm thrilled to read that there are people out there pursuing their dreams!
Posted by: roz | February 19, 2005 at 05:18 PM
I'm really glad you wrote this. Thanks.
Posted by: wynlen | February 22, 2005 at 03:25 PM