Psychologist Gloria Martinez Ayala tells the Huffington Post that coloring triggers and stimulates the brain areas associated with motor skills, creativity, and the senses. Coloring helps to calm the part of our brains called the amygdala, which controls our emotions and stress. Simply put? Coloring takes our minds off our problems, and as a result leaves us feeling much more relaxed, rested, and at ease. Furthermore, experts say that concentrating on a coloring book lets us mentally escape by bringing back memories of childhood, a less stressful time for many of us.
Then you can also create a texture effect. Just cover the drawing with a light stroke first then follow with rough, think strokes to serve as details . texture. This can also be applied when you're using colored pencils. And you can also create a light, smooth look with crayons. Just color your drawing with very rough and thick strokes (this might make the drawing look messy at first) then rub off the excess color with cotton or scratch paper.