Yay I got better! I found a drawing of the Holmes brothers I did two years ago (uh as you can see I wrote 'Mycroft?' considering how unsatisfied I was with how it turned out) and I basically redrew them to see how much my style has improved.
So I'm quite happy to see there is definitely a difference. Of course, I still have a long way to go, but it's encouraging to see that I haven't been so self-delusional that my art remains stagnant.
(For one I have slightly less trouble drawing portly Mycroft now. I feel a bit bad putting it like that, though...)