TWICE a year, Ronald S. Rosbruch, an insurance executive, meets with a strategic business coach to discuss methods he can put into effect to improve the profitability and productivity of his company, National Retirement Planning Associates in White Plains. ''One day, we were talking about hiring,'' Mr. Rosbruch said, ''how to find the right person, of course, but someone who would fit in with the team and stay for the long haul, which can be a problem in a strong job market.''