Many crayon artists (you can find a few online) use solvents to soften their appearance. It can be a wonderful look but, personally, I love the pixilated look the crayon creates when applied just as is. Look at the art examples in this post _ you can see the speckled look crayon has when applied in layers. This adds to the realism, especially when creating an out_of_focus background, such as in these two images.
Coloring Tips and Techniques. First of all _ choose what coloring material you would like to use. There are lots of coloring materials to choose from like: crayons, colored pencils, markers, soft and oil pastels, and many more. It's your choice which media you'll be comfortable in.