Zero Hour pretty much said what you need to do.
Also, i think it's good that he posted, so he knows we are now here to help him, and can crit the images he posts, and ways to improve his drawing. Thats always good, and tutorials are always good to read over now and then, to pick up techniques.
http://www.conceptart.org
http://www.pixeljoint.com
Look at those, gives you a good idea of light and dark, and plenty of techniques, which you can use for both drawing and pixeling.
Keep drawing things like this, post them. And we will help you out, just do what Zero said for now.