My favorite medium is colored pencils, and the best brand (in my opinion) is Prismacolor. I like them because they are very soft and easy to work with, plus the colors are very saturated. If you are going to use colored pencils, keep in mind that you often have to press very hard on the paper to get a solid color. This can really abuse the page and the book. There are two solutions to solve this: either cut the page out of the book and clip it on a clipboard (which is what I do), or slide a thin, rigid sheet behind the page, like plastic or metal. Unless you put this backing behind the page, it could rip or tear, as well as damage the pages behind it.

Unlike markers, pencils require a range of control so that you can make a very heavy mark, which takes some effort, all the way down to a delicate, light touch that barely makes a mark at all. Practice is required to develop this degree of hand-eye coordination and skill.

What I recommend to you is to develop a circular or oval pencil stroke. We learn to color and draw as a kid by zig-zagging the pencil back and forth, making a solid color. With soft-lead pencils, this technique can can create stick points and sharp borders to the pencil stroke, making it harder to blend.

Blending colors is an art that requires you to randomize the shape and direction of your pencil strokes. You may draw the initial area of a gradation with one big gesture (like the blue above), but to make it a smooth and perfect gradation, you'll need to work at it with many, many layers of lightly applied color, slowly building up a smooth, blended tone.

Take your time, be patient. You will not make a good gradation with a few pencil strokes! It takes time to work the surface over and over until you come to a place where you want it. Make your oval strokes up and down for a while, then rotate the page and make our stokes go side-to-side. Then make diagonal strokes. Use a very light touch so that the color builds up slowly.

Gradations and blending are what colored pencils are all about. Practice your gradations and blending on a plain sheet of paper until they come out perfect! Then you'll be ready to tackle the challenging pages.