Those look great! I really like the one where it looks like the start of a fighting game.
And I start with basic shapes, mostly bean shapes and use a reference and make the beans align with the reference. Typically the reference is on a second monitor but I did this one on my phone so I just tabbed between them.
You only know Shang-Chi? Not Iron Man? Hulk? Spider-Man?
Edit: I'm receiving some downvotes, and I can see that my comment looks a bit snarky. It wasn't meant to, I was genuinely surprised at how that was possible.
Ah, I see! No worries, I just thought it was peculiar to only have heard of this character, haha. The drawing is really cool by the way, fun to see him in your style, the lighting is especially nice on this one.