Lots of trotting without stirrups for the rider, and lots of exercises for the horse which take a strong effort.
A longer warm up and cool down with lots of walking then gradually increasing the work. Also use a quarter sheet or a cooler over the horses hindquarters when tacking up., warning up and cooling down to help warm up the muscles and keep the horse from getting a chill.
A longer warmup (and also cooling down). I add a rug on them for the walk and if it’s really cold also for trot.