This is a good starting point. My list of 6 ways to “level up” would look something like this:
You should write that up. I’d read it. I’m just someone trying to improve my networking skills in my own time, rather than a pentester (hence aiming it at casual users).
The article doesn’t mention just how noisy -sV and particularly -A can be on a network. Especially if you’re in a situation where you don’t want to be lighting yourself up like a Christmas tree (e.g. a pentest, red-teaming, reading your boss’ emails).
I’d direct anyone straight to the manpage which gives a good overview of the program’s functionality; a lot of which is often overlooked.