I have a fair amount of knowledge when it comes to "rules" regarding music of the bygone days of the traditional prelude & fugue, the motet, and four voice harmony of the Baroque era. Specifically, the fact that parallel 5ths & 8vas were considered unorthodox, the tritone of a Dominant 7 chord should expand or collapse because of its instability etc...
But what about modern day tonal music? I have played around on my piano with chord progressions that break all of those "rules" and if you'll forgive me for taking the risk of sounding cocky, I sound amazing! ☺ So when we shy away from the rules of 18th century counterpoint to create today's modern musical qualities, why does it work now if it didnt work some 300 years ago?
Furthermore, how do I know if a certain musical idea (i,e. A melody and its accompanying harmony) will work if i were to just notate the music without plucking it out first on my piano? One simple example would be "twinkle twinkle little star" ....using only I IV and V chords I can apply alberti bass while the right hand plays the melody. This usualy works but sometimes a rather harsh dissonance creeps in and I feel like I need to simplify my harmonic pattern to block chords so that those dissonant passing tones and neighbor groups are not obvious.
Is there any clear cut solution?