You’re too kind 
In terms of language features, really any good introductory textbook for C++ (very preferably covering C++11 onwards!) will contain all the concepts I’ve used.
The rest is just naming and organisation - I try to make it as close to readable-in-English as I can get, and break out discrete bits of functionality so that they don’t clutter up the high-level flow of the code.
The absolute best piece of advise I’ve ever been given is: “Write code as if the person who will be maintaining it in the future is a psychopath - who knows your home address.” 