This is a great list.
If I may add something, I'd like to focus on item number two on your list.
You said, "make sure your content is high quality, original and engaging."
That sounds awesome and everything but the problem is how would you know?
So here's one surefire way you can come up with such content without spending a lot of money on "trial and error" content creation campaigns.
How?
Simply reverse engineer what your competitors are doing.
Pay attention to their social media, what kind of content they're producing.
On the other hand, what kind of content are they avoiding?
Do what they're doing.
And once you figure out something that works, experiment, mix and match, slice and dice.
Do what you have to do to build on your strengths and fix your weaknesses.
Still, reverse engineering competition when it comes to social media content is a great way to get a head start and also avoid expensive mistakes.