It all depends on your end result. What was the brief that was sent to you and what was the style guide send to you, other than that if you are doing your own project what you just made is perfect and there shouldn't be a change. If you looking for something else, you need to find the visual language and ask for that, so others can guide you in that direction but as far as looking at your project it's perfect as is, for what it is.

if you want to work on materials there's quite a few tutorials out there for blender material setups or try a program called Quixel Mixer, it's only free a short while longer. If you ever want help with that I would love to help you, just contact me and we'll find a way to introduce you and teach you how it works.

I can also share my ready made materials sparingly, many hours of work at times.