Your drawing is not bad at all. You should learn anatomy, measure the eyes distance to the nose, the space between the nose and mouth, mouth to chin, etc. Also when drawing lines like hair, which is difficult to do, you must remember to start with pencil down on paper and do NOT lift up until you finish the line. From one end to another, it should be one continuous flowing motion.
When you've mastered the skill of anatomy, then you can more on to shading, light, etc. Learn where your shades are. i can see you have the shading on the hairline down, behind the neck, etc. You could use more on the cheeks. Learn to smear your pencil with your fingers for added dimension and shade, don't just press the lead on paper.
Some pencils will smear better than others. But you can achieve this with a pen if you're good by making tinier lines close together and criss crossing over each other like a mesh/fence style.
Go online, go on youtube, there are many artists there who will show you.
Another good tip; find a model. If you're into doing human faces, copy from a picture and really look at it, watch the shades, the lights, the shines of the eyes, and remember the paper is white, so that's your shine already. Draw around it with dark and leave the white untouched for your shine.
The smallest of details will make the biggest difference. Good luck!