I think It does help slightly if you ease off (not lift entirely) the accelerator when you up shift. I've tried up shifting early / late and they are pretty good (unlike the SMGs). For downshifts, I'd leave it to the system to do it by itself, since its the smoothest, unless I want to purposely push up the rpm into the sweet zone for quick burst of speed, off course there's a slight jerk here due to the tranny having to adjust to the engine speed. But Even the DSGs behave like this.
Having said the above, for max performance driving, my pref is putting the tranny into sports mode AND putting the drive mode into sports mode....without needing to meddle too much with the peddles.