When I wore a younger man's clothes, my routine was show up about an hour before my starting time, spend 45 minutes hitting balls at the warmup range, spend 5 minutes on the practice putting green.
A hundred years later, I still get to the course an hour before my tee time. But I head to the coffee maker downstairs in the snack room, then spend 10 minutes hobnobbing with the staff and whatever fellow members who happen to be in the pro shop. By then the coffee has kicked in and my colon is screaming at me that a medical emergency is near... so I find one of last year's issues of Golf magazine out in the foyer and go place my ass on a toilet seat for 10 minutes so it can erupt like Mt. Etna.
A couple flushes and half a roll of the worst damned toilet paper known to mankind later, I grab a few sticks, hop in a cart and go hit balls for 10 minutes, hoping to merely get one airborne. Then after I'm satisfied that no live, active grub worms have been spared between me and the 150 yard flag, I go spend the remaining 30 minutes trying to convince myself that I'm still a damned good putter.
It works, I guess. It's all about routine, as they say.