I would suggest that you look at the frequency relationships in logarithmic space. +-2 = one octave, +-3 = C to G, +-5 = C to E. So if you take any note and th

I would suggest that you look at the frequency relationships in logarithmic space. +-2 = one octave, +-3 = C to G, +-5 = C to E. So if you take any note and then go +0, +3, +5-2 in logarithm, meaning you calculate f, f3, f5/2 then you get a major chord. Once you're working on the frequency ratios like this, you will be able to spot arrangements that can be mistaken for one chord, even though they actually are the overtones of something else. That's called https://en.wikipedia.org/wiki/Syntonic_comma https://en.wikipedia.org/wiki/Syntonic_comma The basis of good harmonic development is then to travel around the harmonic space and then to deliberately produce these dual-meaning situations so that you can use them to jump around in the harmonic space. As an example, consider F-Major, f#-minor, B-major. Implicitly, you are replacing the #f-minor with a g-flat-minor, which is why the jump to B-major then makes harmonic sense. Or as another example, consider F-Major, f-minor, Db-Major, a#-minor, Gb-Major. Each pair shares 2 notes in the well-tempered tuning, but by following this trail you are completely walking out of the C-Major scale that you started with.