1) Begin with mandatory fitness standards, assessed on an annual basis in DECEMBER. Any official who fails to meet the standard has until Feb. 1 to get fit or step down. Veteran officials who can not meet the standards should be offered the opportunity to evaluate 1 game a week for pay.
2) Officials should be given an avenue to police themselves. By this, I mean that, at season's end, officials should be required to identify the "problems" among themselves by a mutually agreeable (confidential) means, then work to correct or remove those problems.
3) Before each season,coaches should be allowed to submit a confidential blackball (or 2) to assigners, eliminating those officials from their games. (This may already be done in soccer. I know it's done in basketball.)
4) Cross-pollinate the officials'/coaches' lists. Each year, identify the top 2-3 problems and directly address their need to accept mandatory remediation or removal.
5) Actively recruit officials by means listed above.