The process for this picture was actually really interesting cause it may have changed my approach to doing finished pieces a lot.
I started the illustration as a normal sketch as I usually do, but then after finishing it up I decided to use curves to change the alpha for the lines, filtering out the parts of the layer with alpha that was very low. That ended up giving a lineart that was actually pretty clean considering it was created from a sketch, and with some quick touch up afterwards it looked almost better than a cleaner lineart, and with almost no time invested.
Another new approach I tried for the illustration was using a lighter undertone for the character, and then painting the darker tones on top right away with a textured brush (colors, shadows and everything). This is much, much faster than filling up shapes and shading them afterwards, but at the same time it looks really good, in a more painterly way, and it doesn't look too distant from what a longer, cleaner approach would take.
The curious thing is that even though I cut a lot of corners in this illustration it ended up looking a lot cleaner than I would have imagined, especially with a cleanup layer on top where I do extra outlines and bring out the shapes more.
One important note is with the background, I struggled a bit with this one cause technically the perspective is not exact, but if I did it correctly it would have probably messed up the composition. I decided to go the more aesthetic but incorrect way, and I honestly believe that this isn't a compromise, it's actually the better choice. I guess that in general in art, going for what looks better always wins over being too accurate. Of course most of the time the correct choice is also the most appealing one, but there are cases where the opposite is true.
I get the feeling that the workflow I had for this illustration is probably going to be my main one once I refine it a little bit, cause the amount of time saved and the end result is way too good to be ignored.