Send the letters and a brochure to the lucky couples. You could offer them a set commission fee each time a referral leads to a taping job. Set up a deal where your photo and video services could be offered as a package. These are attended by people who will be marrying soon, qualified prospects for your services. Have plenty of your brochures and marketing materials handy, so you don't run out.
Most newspapers publish at least one a year.
If your taping was simple, with only one camera, you may be able to deliver the tape to the couple at the end of the wedding. If more extensive editing needs to be done, make sure you give the couple a realistic date when they can expect the tape. Don't give them a time that will leave you rushed. If you don't have your own editing equipment, check ahead with your local cable station. Many times, they have facilities for their public access station which can be rented.