imho, you shouldn't hesitate to create more threads
Maybe you want to devote some to playing games, maybe you want to devote some to specific questions.
A difficulty with using the forums comes with getting adequate advice.
What I mean is that each topic can be approached with varying depth or superficiality.
In the same way, each issue can be addressed from a narrow or a more global point of view.
To start with, I think you should be weary of the more in-depth explanations, because you don't want to be overwhelmed with marginal considerations.
Getting a global understanding of the game will lead you far.
Another key aspect to learning is tied to categorization.
There are categories in the game, such as Wonders, Civics, Great People, City Management, Military, Tech path, Exploration, Diplomacy, etc.
Those broad categories are very numerous.
It's possible to play the game without ever using Great Peoples or without ever exploring but, if you aim to improve, you should determine the aspects that you know the less about.
Those will give you objectives for learning (e.g. what Civics to aim for ? This may have repercussions over your tech path, your trading policy, or whatever).
The more of those categories you can use, the further you can move up in the game.
To play around Immortal difficulty, one needs at least a basic understanding of every of the game's categories.
Conceivably, one could play on Emperor difficulty by focusing only on Wonders, City Management, Tech Path and Exploration, while neglecting entirely Civics, Great People, Military and Diplomacy
But his game wouldn't be very complete, right ?
So, going step by step,
a) focus on the strategic layers of the game (vs turn by turn optimization) ;
b) determine the areas of the game you haven't approached, yet.
e.g. for a) :
The first 50 turns of the game are devoted to the set up of your base.
You aim to set up a strong base, from which to expand and research from.
That means one aims for several cities, so as to produce stuff, and several workers to improve the land, and proper techs to do so, and then basic infrastructure or wonders to propel yourself into the next Era.
Aiming to do so is a lot more important than actually optimizing it.
ps :
If you're searching the forums, you can search for the user
VoiceOfUnreason,
He isn't (very) active anymore but I doubt there's been a better pedagogue on these boards.
