Do not rev and then dump the clutch...that's bad. On cable operated clutches begin to add gas at the same moment you begin to release the clutch. On hyrdaulic operated clutches, let the clutch 'grab' initially very momentarily and then add gas to where the engine would be revving to normally at the gear you are shifting into all the while letting the clutch out. You should not jerk the car; all gear changes should be quick and smooth with the tach needle staying as close to one RPM value as possible.