What exercises should a ballroom dancer do in order to be able to be/become a better dancer?

I would assume that for standard dancers, the forward and backward walk could be practiced.

jphdance. If you look at a top lady competitor it is in Latin very obvious by the muscle tone in the back that they do some gym work. Apart from that you need very strong feet ankles and legs. Hold on to a chair if you wish or without.Do heel raising and knee bending to about 45 degrees. Not the full knee bend unless you wish to. After about 20, depending on your age you will begin to feel the effects. My teacher can keep going ,and going. Play it by ear and don't do too much at first. After a while you will begin to feel the strength in yor legs. Your dancing will also look better. I can tell you without any fear of contradiction that the type of dancer you hope to be have this incredible strength in their feet ankles and legs. I try doing this excecise for
1. 1/2 minutes at a time. My reasoning is in a competition the music goes for 1.1/2 minutes. If I can't do this with the aid of a chair. I wont be able to when I am dancing.

I second what Quickstep has advised, that leg and ankle strengthening is critical. When I was training towards a specific dance test one summer, I went jogging out in the river valley and ran stairs doing several sets up and down with as much foot speed as possible. Of course it is very intense excercise, but the results were worth it in balance, control, posture, quickness, being able to stay on the inside edge (3-toe base) of the foot, and nice glutes as a bonus.

For weight training, I like to do several sets of lat pulldowns with an overhand grip, and also the seated chest pull. Avoid doing too much weights specifically for the shoulders, as this may create too much bulk and make it look like you are hunching your shoulders when you dance. Always try to get a full range of motion in whatever excercises you do, to keep you supple. You should also add stretching. I like to sit on the floor cross-legged when I am cooling down and practice bringing my neck back, thinking about pushing the knob at the base of the neck back and noticing how you can feel that in your muscles between the shoulder blades.

For a different alternative, boxing or punching a heavy bag or hand pads is amazing for developing strong back musles and core strength. Too bad you don't live in Edmonton, I could take you through my whole killer workout.(he-hee)

Yoga and pilates