Reddit mentions of Children's Writers' & Artists' Yearbook 2013

First of all, you need to invest in a copy of the Writer's and Artist's Yearbook.

The section for illustrators is very small, but contains excellent advice. It also contains a comprehensive list, with contact details, of all UK press and broadcast media. This is it's real strength.

It also contains advice regarding getting an agent (a good idea if you want to make a living out of illustration), what you can expect from them etc. It is the bible for self-employed or freelance commercial artists and writers. Well worth £15 or so.

I can't recommend an industry body to you, as I'm not an illustrator. But I can give you an example of a similar organisation to which I belong, which is the Society of Authors. I don't know if you'd be eligible for membership as an illustrator, but if you can find a similar, respectable organisation, I'd recommend it.

The W&A Yearbook should also contain a list of stock image libraries, although you can search for these online easily. Consider the type of work they do and perhaps, when you have little commissioned work on, maybe create images for a stock library. Most do not pay up front, but you will receive usage fees should they be licensed by a client.

Also, there is a W&A yearbook for children's publications. You shouldn't ignore this market. Children's publications consume a lot of illustration, as I'm sure you can imagine.