You want to build up your core as that is an essential, as you see the pro's and see that they can stop in an instant. The best way to improve your core which in turn affects your balance, posture is to do the 'Plank.' Also if you want to work on rise and fall for in the waltz put your feet together and rise onto toes for the count of 5 hold it for 10 and lower for 5 repeat with just one foot