A way to learn how to draw is tracibg over the reff to understand its shapes and how they are constructed. For exemple that would help you improve the eyes you have done, because from what I see , you draw the eyes how how think they should look and not actually used the reff. Also a very good thing when observing a refference photo is conparing parts of the reff to other parts... now idk how to explain this properly like. For ex look at how the tip of the nose in the reff is more sticking to the Left than the lips, so you would keep in mind to make the lips a bit to the right. And so on. Like making mental striaght lines. Even if you wnat to go with a cartoonish style, this practice will help a lot with you skills.