Not bad... Like the color palate and contrasted tones...
I have to bring up, structure and anatomy though... make sure you have a strong anatomically correct sketch before applying medium.
For instance... You were good about keeping the center. But the features on the left side are far stronger and a tad lower than then right, but the feature proportions are more controlled on the right. The right eye is more defined, and the right size for the cheepbone placement... but the right side of the lips do not balance proportionately to the eye above it, stops too shallow (specifically appears to stop pretty close to the farthest point of the right nasal labia... Really study your facial anatomy... Tips, look at other artists facial studies. Practice some yourself.

Look at your sketches reflection in the mirror, so you can see the opposing sides of your art with both sides of the brain. You will find that helps a lot actually..
Anyway hope to see more.. keep it up.. You will get much better at this with practice.