Learn music theory through ear training on common chord vamps - short loops of 2 to 4 chords.

The idea is simple: you can learn to recognize harmonic patterns by repeated exposure in different contexts. These lessons will give you examples, an explanation, and a name (in the standard roman numeral chord notation). Vamps are conceptually simple, easy to isolate and hear, and wildly useful.

Prerequisites: this assumes you know what major and minor chords are, but you don't need to be able to read music or know any traditional music theory. It really helps to have an instrument you can play chords on (a DAW works great) so you can play around with these vamps yourself. But technical skill as a musician is not at all necessary.