Yielding to pressure, yielding the hindquarters and forequarters. Look up some of the natural horsemanship trainers and see what they teach a horse on the ground before they even get in the saddle. One thing I wouldn't do is do a large amount of lunging because it can be hard on their joints (teaching them the basics is fine).
Also, make sure to keep your training sessions short (under 15 minutes) and don't expect perfection right away. You're dealing with a baby. Treat the horse like you would a toddler with a short attention span. Posted via Mobile Device