How To Begin Writing blah blah blah

I've been rooting around in my backbrain trying to figure out how I begin writing a new story. I mean the writing part, not the coming up with ideas part.These days, since I've been writing novels to deadline, it's easy to tell when I'm going to start a new story. I start the new story after the old story is finished. The subject of my story is dictated by what I've discussed with my editor