A fair point. I was shown that technique myself just a week or so before my test, and have used it ever since.
Another good piece of advice I was given was, if you think you've cocked up then just move on. You can get a partial pass, even if you muck up on the navigation, or any other section. Don't let one mistake hound you for the rest of the flight.
As stated, your instructor wouldn't send you for test if he didn't think you were ready.