In addition to Vimjoyer, I really liked the tutorial series from whydoesnothingwork :
https://youtube.com/playlist?list=PLuRxZ95-8LY1mlotZMYGYib5sXJRw1RxW
https://youtube.com/@whydoesnothingwork
For example, there are a lot of install guides, but this playlist also includes packaging and networking guides. This other video introduced me to configuring nix store optimization, garbage collection, and automated updates: