Get a webpage. Then get referral links from many wedding sites.
Make a business page on Facebook.
Use Thumbtack.
Network with other ministers in your state.
If there are any wedding events in your area make sure to attend them. Use professional materials, such as flyers and banners.
Dress the part of a minister.
Make as much a ministry as it is a wedding business.
Network with other wedding professionals in your area such as wedding planners, djs, photographers, etc.
Use business cards.
Get pictures and recommendation letters from each wedding you perform.