Hi, HMD. I've recently taken a look at your art, and you have some good ideas. You have a few areas I would suggest looking at to give yourself a bit of a boost. Here are some crits to help you on your way. PM me if you're wanting any more advice.
When creating a piece of art, have some form of inspiration beside you. This can be your fav anime show, or a great piece of art that is close to you. At first when you put pencil to paper, or use Sketchbook Pro think composition. Never go straight into detail. Block out the body and a pose first. Many people start with the head. But my advice to you is not to. The problem with starting with the head is that a body then becomes an appendage, when realistically the head is appendage to the body. So give that a try.
As for techniques there's a lot I could go into.. But before I start to bombard you, I want you to take a look at this website. When I started creating digital art,a nd anime especially for the first time it was an excellent resource. You have a japan edge to your art, and I know this guy is american but the techniques are there for you to use all the same. So check out polykarbon it's a good website which will help you break into new areas and gain potential.
http://www.polykarbon.com/tutorials/
Stay away from bold colors. if you sample colors from other pieces of art etc you'll see that when they select colors it's never a full saturated color. At times there's more desaturation in it which gives impressions of light and darks. Once you are familiar with Polykarbon, and have done a bunch of new drawings hit me up again, and we'll see how you are progressing, and I'll point you in a direction of new materials to push you into new unknown territory which will enhance your ability. Good luck! You have potential, it's just a matter of unlocking it.