How Do We Make It Easy for Passive Referrals to Happen?

For every one of those passive referrals that shows up on your doorstep there are probably at least three to five times more times that your clients recommended you and they didn't follow up. I can't think of any business that wouldn't benefit by having a monthly communication with your clients if it's a monthly newsletter or some sort of a communication that you are regularly in contact with your clients so that they're constantly present in that relationship. So how do we make it so that it's easy for those three things to happen?