I think this is a good writeup, and helpful for developers who taught themselves from video tutorials. I also agree with most things.
Regarding git: it's not mentioned here, but I use bitbucket to host my repositories. I think it used to be the only one that allowed for free private repositories. Git has a learning curve, but it's worth it, even for solo developers.
Regarding unit testing: it's done a lot less in game dev, compared to other fields. Not because game devs are knuckle draggers, but because it makes little sense for real time systems that interact with other real time systems (how do you unit test your player controller? I'm sure someone can come up with a theoretical, academic solution, but that's just not practical). That said, if I have an isolated, discrete system, I add unit tests (or at least I know that I should ;-) ).
I liked this blog post about professional testing methodology for games: https://tomforsyth1000.github.io/blog.wiki.html#%5B%5BLogging%2C%20asserts%20and...