On Keeping the Aspects of Composing Isolated

According to Walter Piston, from his iconic orchestration book, "The true art of orchestration is inseparable from the creative act of composing music." Although I understand his meaning, from a practical working aspect I have to disagree.Perhaps one of the hardest lessons for me to remember and adhere to is this: the more I separate the different aspects of scoring, the better the final result will be.Usually when I sit down to score a scene, without being aware of it, I am severely multitasking. I'm simultaneously making dramatic decisions; writing melodies, counter-lines and harmonies; orchestrating; producing and mixing. Much like any other kind of multitasking, when you're doing everything at once you're devoting your full attention to nothing. What I've always found to work better is to isolate every aspect of the process and give it my full attention before moving on.For example first I might watch the scene to figure out how it fits in the overall structure of the film and what the music needs to say. Next I'll dissect the scene for specific beats, hits, and shifts, and come up with with some basic ideas for tempo, harmony, and so on. Next I'll write the whole cue in as few voices as possible, usually left and right hand at the piano, sometimes maybe just a single melody line. After the entire sketch of the cue is complete will come orchestration, and only after that point the final production and mix. It sounds very obvious, but how many times have you caught yourself EQing the strings before the basic skeleton of the cue was even half written?Composing music is a messy process and I believe that you can never truly live up to the ideal of total separation. At some point you'll be mixing the low strings and come up with a better part, or as you orchestrate you realize your harmonic progression lacks direction. But just because you can't have the perfect doesn't mean it's not worth pursuing.When I am mindful of the idea of keeping my processes separate, the music will be better.