Let's first start with using crayons. It's usually one of the first coloring material introduced to little children because it's perfect for kids to use since there's jumbo sized ones that they can easily handle without breaking it in half. It's also a great material for bigger kids and even grown_ups because it has a wide range of colors to choose from.
Soft Pastels are interesting media to work with. It can also be fun for you can use your own fingers to apply the color or you can use a brush or cotton balls.Just outline the drawing with your chosen color and smudge it with your finger, brush or cotton. You can achieve a soft, hazy look with this just like the one in the picture. Plus, you can actually erase smudges using eraser.