Seems like a big part of improving has to do with finding increasingly comfortable methods of working. I've realized that my work goes much slower when I enter into a piece without confidence. For years I'd say I've continued a practice that leaves me with no confidence when it comes time to render. Going into photoshop with loose sketches. It locks elements into locations but forces me to flesh out the full structure and details on the fly. This gives me some hesitation and I work much slower. I seem to work fastest when I have a detailed line drawing going into photoshop OR if I'm going into photoshop with practically nothing at all.
I may have been aware of this subconsciously for a while but I really get impatient with drawing and rush into photoshop when something happens where I like an element but want to re-size it or change the angle slightly. Also, I don't enjoy drawing in line. I prefer to erase out of a base or work with bigger charcoal marks. I think it's been a process problem that I've been avoiding addressing. Well I think I've finally found a more relaxing process that also allows me to head into my digital finishing with more confidence.
In the past I've done thumbnails to work up comps and they've literally been the size of a thumbnail. Lately I'm instead starting at a larger size which I've always thought was insane because I'd never tried it or heard of many artists beginning that way. I've been getting out big sheets of cheap paper and doing more gestural charcoal drawings to work on my characters and comps. Takes the focus away from line work and puts it more on proportions and pose. After I've got some good poses I get out marker paper. Marker paper is a lot like tracing paper except sturdier and can take more erasing. It also won't have all of those crinkly lines you'd get from scanning tracing paper. Using the marker paper, I can turn my messy mass drawing into neat line drawings that I can flip over to get a fresh perspective. Then it's easy to do another layer and adjust any proportions or angles I might feel could change. Then I can use a micron to go over the lines and then really pour on the markers. Then I scan in all of the individual elements and combine them.
I used this on my latest entry for Art Order and I got the piece done very quickly. I'm currently using it on a illustration of Kali with all of her arms fighting 4 other characters. Such a busy scene might have slowed my working to a crawl with my past habit of doing the most minimal drawings. I always thought I was taking a shortcut but I think it likely caused me more stress.
Anyways, get out there and try some marker paper if you haven't. It's nice stuff to draw on.