I think I've identified an unfulfilled need in our current online environment, have an idea of an end-result that could flourish, and some possible ways to monetize without being a cancer on society.
I have some experience with basic site-building, but this would be a very ambitious project for one person. It will probably take a long time before I get it going—if I get it going at all. I know some of what I need to start learning to make it work, but my mind doesn't know where to start when it comes to security, stability, or scalability.

Security:
This is probably my biggest concern. We hear all the time about data breaches, and this idea is—at its core—a kind of social media; by its nature we're dealing with PII.
Where does everyone go wrong here, and how do I protect the information of potential users?
All I've got is I know that storing passwords in plaintext is a bad idea, and to encrypt 'stuff' .

Stability:
I'm sure we've all experienced a site going down to a heavy load. Say I can get a site up, and things go well for a bit, and then somebody with a big twitter/instagram/youtube audience says something and a hoard of people come to check it out. A site going down when you try to check it out doesn't leave a positive impression. Can this sort of thing be prepared for, in the possibility such a thing ever happened?

Scalability:
If I can get a workable site running, I don't expect much of a userbase for a while, if ever. But if it does get large enough to attract hundreds of thousands, or a million+ returning users, it would be nice if I could have the architecture in place to handle that ahead of time, instead of playing catch-up later. What makes a site scalable, and is there any reason it can't be prepared for?

I'd love to be able to pay some folk to help me, but I don't have the cash for that. The initial launch will have to be done by me alone, so I'm fully prepared to learn what I need to and take the long amount of time required (maybe next summer?) to get the minimum product going. Even if this ends up not being feasible to get going alone, I figure the worst case scenario is a lot of learning along the way.

I am beginning to reintroduce myself with web app development and have about fifteen years of classic ASP/ASP.NET under my belt.

I’ve decided to continue on with my decision to learn Ruby on Rails.

In retrospect, my university professors passed only one (as best as I can remember) best practice onto us fledgling programmers:

Documentation

Besides documentation, are there other general best practices to consider?

And, specifically, are there best practices when developing with Ruby on Rails?

I come from a background of classic ASP/ASP.NET programming. I had about fifteen years of professional experience with it and completely stopped all programming around 2008.

Now, I want to pick up web programming again. I looked at and tinkered with Python, .Net Core, as well as others.

I was, particularly, impressed with Ruby on Rails and have completed about thirty hours of training through The Odin Project.

Before I continue on with ROR, I just wondered if I may have missed something out there that could turn out to be a 'better' option for me.

What are your thoughts on ROR? Would you recommend some other framework? Why or why not?