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.
For beginners I would suggest either the Staedtler or Faber Castell brand of pencils. These produce significantly better results than bargain bin pencils, provide good colors and allow you to try some simple shading and blending techniques. With practice the best coloring results can even be achieved with the most modest tools!