Highest possible rendering quality for visualisation

Hey guys,
I’m currently working on a project where I need very fine structures (paper art, Noriko Ambe type paper sculptures) to look great inside the engine. I already made progress and it looks nice. I was just wondering if I can up the quality even further. Are there guides or tips you have to achieve the highest quality possible ? FPS doesn’t matter at all here since it’s just going to be a still image.
I think especially the shadows are important to be finer and better and the anti aliasing should be improvable as well.I don’t mind having to edit the ini files as well.

Would be awesome if you guys know something in store.