Only way to make anything perfect: a lifetime of practice. Or two.

Also browse this forum and gallery and study other artists work, how they used their colors and what they have to say about it.

Just do some stuff and post it here, we can only help from something you actually do. Best thing to start is to use an imposed palette, however crazy it may look. There are palette challenges on PJ and Pixelation too, just pick one. Don't fear to fail, one learns a lot more from one's mistakes than successes.

Check some tutorial links too if you want (they're everywhere), just don't expect too much from them.