My mistakes will be intersectional or they will be bullshit

Is there any kind of across-the-board best-practices guide for accessibility in web development?

(I'm thinking about tags and whether screen readers try and ignore them and whether that harms the Authentic Tumblr Experience for non-sighted people - because some of the tags are tags, but some are instead marginalia. Or, in tanb...... slime man terminology, "marg targs."

I'm aware that that particular thing's not the first priority! It's just, for optimization purposes, I was thinking I might try to ruin the subversive thrill that comes from misusing tags by classifying some tags as marg targs and thus not trying to index by them, which led to thoughts about whether the marg targs should/could be marked up differently somehow so as to be caught by screen-readers.)