The NTSB recently issued four safety alerts for general aviation pilots and mechanics: Mastering Mountain Flying, Understanding Flight Experience (A rating alone cannot ensure safety: Training is key); Pilots: Perform Advanced Preflight After Maintenance; and Mechanics: Prevent Misrigging Mistakes.
Each of the alerts, in PDF, includes an outline of the problem, summarizes related incidents and accidents, then lays out what the mechanic or pilot can do to avoid the problem.