Apply what you know about visual arts to music. It's all art and the rules are similar. For example :
- If you use only the basic colours (chords, scales), you will (most probbably) get a basic, naive looking painting.
- If you mix too many colours you get brown (noise).
- Think about what you want to paint, prepare the colours you need, make a raw drawing first and then apply colours...
If you spend some time thinking about these "rules", you will find them applicable in most of the "structured forms" in life (like art). The difference is the expression. Generalize it and you'll find the one-rule-fits-all, and that's the meaning of existance.
O.K. I got way off subject, but there should be some sense to it.