Yes, I very much agree with Eldiente that I wish more people would use rope or visual signals to minimize yelling. Yelling commands is annoying. Yelling should be reserved for mighty yalps, badgering the leader, sasquatch impressions, and other expressions of joy.
My rope signals:
When leader is off belay, he/she pulls up about 20-30' of rope as fast as they can. This should be much faster than one would be climbing, so it is a clear signal to belayer that leader is off belay. Leader then pauses for ~10sec to allow belayer to remove belay device. Leader then reels in remaining slack, puts second on belay and gives three tugs to signal second is now on belay.
My visual signals:
hand cutting across the throat sign = leader is off-belay
waving towards me = come on up, you are on belay
middle finger = you are my friend and I like you