There are lots of tools: pencils, markers, paint crayons. Each material has its own characteristics and advantages, promoting the development of specific skills. It is recommended to start with pencils.
There are different varieties of coloring books nowadays, so that all you have to do is decide whether you need it or not; today you can even download the application for coloring. Currently there are more colorings to choose from than ever before, just select the coloring with your favorite motives, print it out or download the program from coloring website.