Are you talking about training for all officials, inexperienced, and experienced? Or just new, inexperienced officials?
For "continuing training" for all officials, our local interpreter chooses his training topics in two ways during the season.
1) He is always open to take emails and phone calls from officials who have questions regarding rules, situations, mechanics, etc. He answers these individually, but also brings up some of these topics to the entire membership if he believes that they will benefit the entire membership.
2) He always watches three periods of the junior varsity game before his varsity game. From these observations, and what he may see in his varsity games, he will bring up rules, situations, mechanics, etc., that he thinks would benefit the entire membership.
For example, game management seems to be a reoccurring topic.