Contrary to popluar beliefs, expensive computer programs will NOT make you any better. Actually, it might make you even worse becasue you're constantly having to rely on Undo and filters and other shortcuts that make your work seem fast and cheap and unpolished.
My reccommendation is to stick with the colored pencil and take some time to learn how to use it and learn what you can do with it.
You're using colored pencils like most people start using them- just to color in the lines and only use one color and pressure for each part.
The wonderful thing about colored pencils (Prismacolors in particular) is their ability to blend.
The more colors you use to shade with, the more depth and richness your color will have.
Coloring a Green Chia? Don't just use the green pencil, use light green, forest green, seagreen... Use as many different colors as you can along with the normal green.
When you start getting more advanced with your technique, try shading with color compliments- in this case, it would be red.
Also, layer your colors and apply it with even strokes so that the white of the paper doesn't show (except for highlights and such). Don't be afraid to shade (heeh, that rhymes.), and always try for a lot of contrast in shading. It'll make your pictures pop and look three-dimensional.
I also redlined the chia for you, it's expression just wasn't working for the emotion he's supposed to convey.
I hope all this rambling of mine helps you, and don't be afraid to ask questions if you're lost. Good luck, and keep it up!