In the diagram below, the left side demonstrates how two in-phase waves sum to an amplified resulting signal. The right side demonstrates two precisely out-of-phase waves are attenuated to silence.
It’s an ever-fluctuating continuum. Sometimes an idea will pop into my head completely orchestrated and ready to be written down, and other times it’ll just be a little scrap — something I have to sit down and futz around with for hours before achieving any sense of clarity about what exactly I should do with it. Orchestration has always been my favorite part of the writing process, and I enjoy trying to figure it all out, digging and finding the information already hidden in a piece of musical material that will guide my decisions about how to treat it.