>look at what professors are there, and look at things like what books they've written, have they written any interesting blog posts about their teaching, and that sort of thing.

I wish I did this. I basically applied to Universities ranked highly for my degree at the city I wanted to be in (London) before realizing these rankings are near arbitrary. It was only in my first or second year as I read more papers that I realized I should look into what Professors there publish and was largely unimpressed or didn't care for their subfields but it was too late by then.