Basic Pillars of Knowledge to learn

[Gere W.]

What would everyone consider fundamental categories of things to learn about in real estate? ie. pillars of knowledge

What would subsets of those fundamentals should you learn after you have the basics down?

When do you know enough to start realistically? How much do you need to know? 

I realize the above can all be answered with "it depends" and it certainly does. Moreso, I'm looking for general direction to plan on what to learn. 

Investing in real estate is turning into paralysis by analysis. I'm starting with the podcasts, and I've just started reading the BP rental property investing book, but just want to flesh out ideas of where to start. It's overwhelming and I need help paring it down into bite-size chunks. Here's my ideas of pillars to learn. First one is an example of what I'm looking for. 

Pillar: Financing

   Subsets:

       i. conventional loans (20% down)

ii. FHA loan (3.5% down, first time home buyer, house hack)

       iii. et cetera

-Analyzing deals

-Developing a Network

-Estimating Rehab Costs

-Taxes

-Legal stuff

-How to plan for it all

What else to add? Useful subsets of each one to learn as well?