The material. Some coloring books offer the ability for the child to simply run over the surface with the pens or crayons provided, and it will turn out to be the right color regardless. Some are more like paint books, and some have magic marker surfaces and come with markers that will not show up on any surface but the specially prepared book pages. Choose the book that best suits you and your child. If you are worried about markings on the walls, then dont select a pack of basic crayons, get something that uses special crayons. If you want your child to exercise their own creativity and not have to fit in the lines or color schemes planned, get basic pages. It is up to you.
The art of coloring is a simple joy. All you need is a coloring book and your choice of tools. From here you can immerse yourself fully into the craft without agonizing about what to make, how to read the pattern, and how will it turn out? Coloring is a a form of meditation. There is something truly hypnotizing that happens with you sit down with a fresh box of pencil crayons, choose the color that jumps out at you and begin your journey into the page. Time loses its grip on the mind and enables the color-er to become present in the moment, in the line and in the color gliding onto the paper.