You could try a half halt or two? Just do a quick squeeze (give and take motion) with your outside rein. It should make your horse listen to you more and collect a little if your horse is well trained. :) She may also mean she wants to see good impulsion in your trot/canter when she says she wants rythm and regulation of the gait. With most horses, a short quick squeeze with your inside leg may do the trick! This is just my opinion with what i've learnt, other people may have different ideas, so give them a try and see if you get any results, good luck!