What makes a good children's picture book?

One thing I've learned through writing and selling is, children just seem to love rhyming books.

Out of 6 picture ebooks I have on Amazon, the two rhyming ones outsell the others by around 3 times!
I think really young ones can pick up on the rhythm, and enjoy the musical feel of a rhyming book. 

Put with simple ideas, thet children can easily relate to, and clear colourful illustrations help make a good picture book.
What do you think makes a good picture book? 

Paula xxx

Here are my two rhyming ones

http://www.amazon.co.uk/Hairy-Spider-Childrens-Picture-ebook/dp/B005HFHI26
http://www.amazon.co.uk/Slippy-Slimy-Childrens-Picture-ebook/dp/B006AV1W9Q

Children's Picture Book "Slippy, the Slimy Slug" doing well!

My latest book "Slippy, the Slimy Slug" is doing really well.
I'm so pleased!
I've had some lovely comments, saying the illustrations are clear and bright and the youngsters love them.  It seems rhyming books are still very popular. My other rhyming book "Hairy, Scary Spider?" is my best seller in the UK and in USA.
I've also put them on my website - I think that helped.

Check out the sample pictures, if you wish, on my website.
www.tothewillowgarden.co.uk