I've worked with 3D Modelling for a few years and only recently got into realism. It is still admittedly a work in progress but I like to think I've come a long way over my years working in Blender.
I worked on photorealism, or as close as I could get with the tools I had, and to achieve this I needed to practice realistic materials. I definitely feel that I've improved on my photorealism and would count this project as a success.
Photorealism has three main elements: Lighting, Materials, and Scale. Lighting and Materials are arguably more important but they are still all a necessity to achieve true photorealism.
In order to make photorealistic materials a lot of things have to be considered. Nothing in our world is perfect, there will always be smudges, smears, cracks, chips etc. and so this has to be taken into consideration. It is hard to notice but there is very faint smudges on the floorboards above which helps tie together the realistic look.
All of these renders helped build skills I needed such as UV Unwrapping, applying textures + bump maps, achieving certain materials such as metal, and creating composition.
Credit to NASA for the various maps required to capture a realistic render of Earth
Credit to Game Freak for Melmetal's concept
Credit to Lord of The Rings for the concept of The One Ring/The Ruling Ring + The New World map
Credit to Hello Games for the Exotic-Class Squid spaceship model
Textures were licensed under a CC0 agreement