I made a list of all the website I've made which haven't made a cent and the lessons I've learned from these.

Would be good if you could add the list into the post here to reduce the click trail.

Anyways, cheers for sharing. Some interesting ideas there, key principles that struck me:

1. Build something you would use yourself.
2. Execution > idea.

Warning - contains ideas you can steal.

I think you came to the right conclusions on these other things. I’ve been guilty of starting things that sound like they’re going to make money but when it came down to it, didn’t have the passion or experience to continue, or to stand out.

I noticed that the sites were derivative. Meaning a smaller (idealized as "more niche") version of something that is already successful. Flights in Uk vs Everywhere. Indie numbers vs indie hackers, ski resorts vs Nomadic Cities.
reminds me of this X for Y: https://andrewchen.co/x-for-y-startup-ideas/