Your metronome idea is good. It's the whole rhythm concept in your head. I don't use a metronome but I do go through sort of a standard check list in my head as I'm drawing and setting up to get my shot off. It runs quickly through my head as I am doing it but to a specific rhythm that I almost keep a beat too.
It keeps me focused and where I don't stop and dwell on any particular thing.
NRA Certified Pistol Instructor, Home Firearm Safety Instructor, & RSO
On the range again, just can't wait to get on the range again. The life I love is shooting guns with my friends, and I can't wait to get on the range again!