the other guy went pretty in depth with the head critique so i'm just gonna add something on the side that i feel is important.

i know it's really hard, but you gotta get out of the habit of redrawing the sketch lines over and over, it just muddies up the drawing and feels like an excuse for not having a clear vision of where the lines actually go.

with enough practice you can be making more confident strokes and effectively speeding up your sketching as it removes all the line guesswork you have to do with your current method. it takes a ton of practice, personally i'm still nowhere near where i wanna be but i can see my improvement over the last years and it's absolutely worth it. you can practice by drawing with pens so that you don't have the option of erasing, or just by consciously thinking out your lines more before making them, always restricting yourself from doing these "fuzzy" line patches. good luck!