To always end on a good note which means some days you may only work for 5-10 minutes. Once you accomplish something even small its good to reward for effort and not push them any further
This also depends on what you mean by young horse as a 3 year old is very different than a 6 year old but both considered young horses
When you are learning a new thing imagine what you would do imagine if you are about to go on a theme park ride which you are scared of treat the horse like that and the number one rule... patience.
Hope this helps