I read and collect the children's book reviews from the Globe & Mail and the Toronto Star newspapers. The reviewers are Susan Perren and Deirdre Baker, respectively. Their recommendations are excellent.
Use book lists.
The Toronto Public Library offers a selected book list for children and teens. It's free.
Buy a copy of Best Books for Kids & Teens 2009.
A magazine published by The Canadian Children's Book Centre. Available in bookstores or their website at http://www.bookcentre.ca/.
Here are some good ones:
by Deirdre Baker and Ken Setterington
edited by Anita Silvey
An indispensable reference book; I use it often.
by Anita Silvey