Almost all of my bookings are referral....by past clients, guest of past clients, venues & other wedding vendors.
With most of my clients, I've connected with them via FB. I interact it with them before and after their wedding. I create personal friendly relationships with many of them. I give them special attention throughout the planning process. They rely on me before, during and even afterwards.
Client guests are also important as you never know who a potential clients is or where you'll meet them. Guest get an advantage over a cold-call inquiry as they are getting to see you in action; a silent interview per say. I give out approximately 10 cards each wedding as they come up and ask for information. It's nice that I can have my assistant slide over to manage the music while I can devote some attention to them directly and spend some quality face time with them.
Venue managers are great to connect with. They know the good vendors who respect their buildings. Many of the places I play, I have free reign to the electrical box, keys to the building, closets to store my gear instead of having to pack it back out to the trailer, etc. They'll open up the building for us and leave, trusting that we'll be there to help watch over things. Since most brides are quick to wrap up their date for a venue, they are also asked quite a bit if they know a good DJ. I keep stock of cards & brochures in their hands.
From my experience, the most popular vendors (and the ones that I connect myself with) are the ones that treat their clients more like a friend vs. a person who just signs them a check. The ones I'm networked with are at the top of the tier in their professions. We all have one goal in mind; taking care of the couple & go to extreme lengths to make it happen. I think that extra is reflective in our rates and the fact that when our clients are asked, our names are mentioned as 'must-haves'.
I've mentioned it before and I don't want to hurt anyone's feelings, but it's just my opinion that if you're not getting a majority of your business from past client referrals, then you're not as good as you thought.