There is still a way to go, but keep going.
A few tips that worked out for me that maybe you want to apply:
1. If you feel like the face shape is off. Or the placement seems wrong. Use a foto of a real human and place it over your drawing, you will see instant what is off. ( You can also apply the basic steps, drawing a cirkel etc.)
2. Instead of making small lines at a time, make 1 fast stroke, ctrl-z is your friend. This will give you a smoother line, it might take you allot of tries, but if you hit the mark it will look much better.
3. Mirror your piece every now and then, your eyes get used to mistakes very fast, this way you re-adjust your way of looking. [ctrl-a], [ctrl-t], [right-click] turn horizontally.
4. Take a further look from your drawing, zoom out and take a few seconds to look. Or take a picture and look at it during your breaks.
5. For more dept you might want to use darker shadows, it will take some getting used to.
6. If there is 1 lightsource (like the sun) There will be 1 spot that will catch the most light, the rest will be a tad-bit darker. Try to keep in mind where your light is coming from and which parts will only get a little or none.
There are many many more things, but I hope this helps a little. Keep it up!