Before starting you need to make sure the horse is at the proper weight. If you feel he is at the proper weight to start an exercise plan make time to ride 4-5 days per week. Find a hill with a gradual incline. The bigger the better. work walk, trot, and canter un and down the hill for a couple weeks. Now do the same hill work this time get into two point lean down a little put each hand as low as you can on each shoulder. Keep good contact and send the horse forward into the bit to engage the hind end. Few weeks of this you will see dramatic improvement. When starting the two point exercise do it in spurts. The horse should not be forced overnight needs to be gradual.