Colored Pencils is one of the easiest media to handle since they're pencils and you can control your strokes well. There are also a lot of available colors to choose from. First, cover the entire drawing with light strokes. Then, you can proceed with the thick lines to add texture and effect to your drawing. You can also add some more details in your drawing like this one. Soft pastel was used for the blue shadow_effect.
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!