How can I improve texturing and lightning ?

Hi everyone !

I just started Blender 5 days ago, and after finishing some tutorials (especialy the doughnuts one), i’m trying to start a project on my own. Basically, i’m trying to create a big wheel, but the thing is, even if the modeling seems to be OK (I guess ), the textures and ligntings just seem off … https://imgur.com/U08lP1G
Any tips for a total beginner ?

They’re not off, they’re just very simplistic.
What style are you going for (lowpoly, cartoonish or realistic) ?