You must broadcast the message consistently at every meeting, at every opportunity, and in every newsletter. Plus, you must be specific about what you are looking for in the employee. And, it must be worth your staff's efforts. Smart firms are paying bonuses in the thousands of dollars. One Big Five office not only pays bonuses, but also enters the referring employee's name in a quarterly drawing for a Ford Bronco.
Smart firms use state societies as farm systems to recruit.
One Chicago firm has two semi-retired partners who attend the society meetings in an attempt to cherry pick the best from other firms. I have found it amazingly easy in such environments to get employees of other firms to open up. Ignoring college campuses Smart local firms don't neglect colleges. They want to create and secure their own culture, not a mish-mash of training and bad habits formed by hires of other firms. We find grads aren't interested in local firms.