You've captured some really compelling poses with economical lines. They have an energetic comic book feeling.
I'm curious which practice format you used, this looks like all the same time per image.
In terms if improvement, I notice your feet are drawn consistently proportionally larger. I think in many cases it fits with you style and makes for strong grounded silhouettes. That said you might take time to focus on your feet when you do a session and see if there are other techniques to capture them. It can help capture the complexity of poses where the limbs aren't grounded or bearing a lot of weight.
I took a look and at first blush I'd say they're looking more consistent than you post suggested. I also struggle with variance in quality and I have different styles that I'm in the mood for.
I understand why you might notice it and want to address it, but it's also a natural part of the process as the reference image quality, lighting conditions, etc. The size of the character available on the page, and the challenge if the individual poses also have an impact.
To that end I'm wondering if some of the poses your less happy with have a pattern. Do you find they're of a gender, body type, or pose style that you find easier or harder?
what follows is more of a hunch / conspiracy theory I've started to develop over the years: I was taking a class recently on stylized character design after years of mostly drawing and painting from reference - and I realized that comic artists really craft idealized versions of their characters. They use reference and then assemble the idealized pose that's the easier to make look good. And it can be so subtle you don't recognize it unless someone's breaking down what they're doing as they're doing it. It's like "natural" makeup - it's still makeup and it makes a big difference in presenting.
Much longer ago I was working with my art director and watching her work and noticing that she was sidestepping issues of complex muscle behaviors in favor of more confident construction. There's subtle tweaks you can do later once you're in tertiary details to bring some of that messy reality back. It seems less like cheating to me, and more being gentle with yourself that you don't have to be so caught up in highlighting the hardest (and least aesthetic) parts of a particular still frame pose that a photographer would direct their models to change.
I think more seasoned artists get used to this pose sweetening - and their canvas of gesture studies incorporate that into their sketches. The final result is a pleasing - inspired collection, not photographic accuracy.
I spent years bouncing between still life and life drawing and where there's less rooms for interpreting gesture and I think it broke my brain a bit feeling beholden way past the utility of making sure you're drawing what you see and not what you imagine.
