It's not bad. The trick to "getting better" is just sticking to it, no matter whaaat. Its a great place to start from, I see the shading and stuff.
If you want more precise shading, get a pencil set with varying softness/types n stuff. Its designed for that. Otherwise you might not get too much variance in shade, but you seem to convey texture in a unique way.
tl;dr Cool stuff, stick to it and there are special pencils for varying levels of shading (I think).