A substantial proportion of the current 'rules' of aesthetics stem from the early Modernist period. One of its principal exponents, Johannes Itten, published an extremely influential book in 1963, The Art of Color, dealing with (unsurprisingly) colour theory. However in its original preface, he wrote something well worth remembering. I don't have a copy around, but it went something like this:
'Rules are extremely useful to guide one forward in one's weaker moments, but when one feels the power of beauty flowing though them, they can be discarded without predjudice, and the artist can perform to the utmost of his or her creativity, freed in the experience of synergy with the universe.'
