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.
Coloring is a great way to bond. Ask your friends over for some wine, cheese and coloring. Perhaps at first they might look at you with skeptical eyes and doubt; but hand over a fresh sheet of paper, some vibrant or glitter colored pens and in just minutes you will not be able to pry those colors out of their fingers. Soon you will be visiting easily, looking over at each-others masterpieces from time to time to admire their selection of colors. You will begin to feel like you have time-traveled back into grade 2 and you do not really want to leave. Coloring is freeing and has no expectations. The beautiful thing about this craft is that there is no pressure to finish, to use a certain color or even to stay in the lines!!! There is absolute freedom involved in those precious hours where you just get to color.