In addition to below

And to add on to what you indicated about behavior controls: implement some form of a RESPECT campaign. Measure behavior of players, coaches and parents. We use a 1-5 scale locally, but whatever works. The referees actually do the judgement. The numbers are published and clubs are held accountable to poor numbers in any area.

Parent education is a huge help in this regard, but many behavioral problems at the youth level are propagated from the coaches. They set the standard, generally. They should be held to the highest standard of anyone. The kids are kids and the parents are generally ignorant. No excuse for the coaches.