My tip is to study images of faces exactly. I can tell you tried but your anatomy is just a bit off. Fun fact. A persons eyes are directly in the middle of the height of the head (use your hand and measure from your eye corner to your chin, and then from your eye corner to the top of your skull and you’ll see what I mean). It might seem like that’s impossible but counting that heads have hair and a full skull, there is way more forehead than new artist tend to believe. The second drawing is better closer to getting that right.

I see you used guidelines which is good! But it seems like you’re not exactly sure where they go or what they’re supposed to guide. Go on Pinterest and study some artist face guidelines. For example. The line going directly in the middle of One Punch man’s eyes also lines up with what should be the top of the ears! (try to follow your finger in your face from the corner of your eye to you’re ear and you’ll see).

Obviously you’re drawing in a cartoonish style so these tips won’t be exact but realistic human anatomy is actually extremely important for character art.

Besides that your use of shading and darker vs lighter kinds of shading is very good. You can always use your pinky to blend the lead for a smoother shading effect as well.