Watercolors by Mari Bolte, illustrated by D.C. Ice is one in a series of books called 'Paint It' for third to fourth grade readers. They are non-fiction, teach the basics with papers, colors, brushes, and what to do with them. It has reliable information, although I'm more of a learn it as I do it type person.
This title does have several lessons to practice and try along with instructions. It shows how to use washes, glazing, and mixed media techniques. There is a very cute exercise making cupcakes with lots of different ways to make texture.
I would use this with my home school group or after school groups. They would love to experiment with the different styles this book has to offer.