The best drill I use is to take 3-4 balls, start about 3 feet from a hole and work all the way around the hole, trying to make 18 in a row. You miss you start over, when you get to 12 or so you start feeling the same pressure that you feel on the course. If you get to where you can make 18 in a row, knowing that you only have to make one at a time on the course seems easy. Also when you can make 18 in a row go to 27 or move back to 4’