Thanks, I'm happy to read you like the art!
I really only started messing around with 3D art a year and a half ago. I'd say what helped me the most, beyond just learning how to navigate the 3D program I use, was reading up/watching videos about photography and movie lighting. "Rule of thirds" is a pretty easy, basic photography concept when it comes to framing images, and I generally follow it. But I think lighting is most important. Looking into how they do lighting for TV/movies helped me figure out how to light my own scenes. And then after rendering, I do post-processing in GIMP to do things like sharpen the image, add contrast, and bring out certain colors.
I'm not an art expert by any means, but I hope that helps 🙂