Consider current and past buyers as the V.I.P. part of your customer portfolio and focus your time on existing and previous buyers.  Develop a separate and personal communication strategy to engage them by exclusively sharing special news, lesser-known services, private incentives, and gatherings and receptions.  

Find a method for follow-up calls, contact, and keeping fastidious notes within your CRM.  Existing customers can be fanatically loyal, repeat buyers, and the best referral service you could ever dream about having if you remain loyal to them.