The owner of our company is into racing GT cars and has been for the past twenty years. Has an engine builder he drives down South to pick up (two each year). He swears by the following method..
Take the car to a long straight.. Load the car (full throttle) in 1st from idle to 3,000 rpm (he used to V8s so I would say maybe 4,000-4,500 for our smaller engines), shift to second and load the engine again to 4,500, shift to third, so on and so on until you are in the final gear at 4,500....
Then (keeping it in the final gear) left off the gas and allow it to coast (not a correct term, keep it in gear and do not engage the clutch) allowing the engine to slowly return to idle.. When at idle, downshift and allow to return to idle, and so on until you are back in first going about 0.
Do this again for about 4 or 5 more times.
I tried it with the Contour and the results were fairly good, but the next time, I'll probably just follow the manufacturer's recommendations...