I think a thing to look out for is lines in relation to other lines. Particularly on the right boot, if you use other lines in the boot as a guide (like what certain parts align with higher up, to the left/right, etc), I think you’ll find your line relationships will be stronger.

Good effort! I think you need to think more clearly about dividing the portrait into the light and dark portions. Only then, once you have that blocked in, should you think about sub-dividing them into first and second shadow, half tones and highlights. To summarise- you're using similar values on the left and right side of the face, but if you look at the reference the right side is much darker- squint and you can see there is a big block of shadow on the right and a big block of light shades on the left. Block those in as large groups- then think about breaking them up into smaller shapes. I think if you try to think in big groups first you might find you get the proportions more accurate too.