Figure out what your niche will be. Businesses that provide music for weddings loosely fall into two categories: bands and disc jockeys, also known as DJs. Bands can be much more work to maintain and put together, but they also tend to command higher fees. DJ services typically do not charge as much as a band, but they are usually cheaper to start and maintain. When starting a business, focus on just one to develop.
Make sure you can provide appropriate music for all of the aspects of the wedding---the ceremony, cocktail hour and reception. Have a variety of music, including traditional ceremony, light jazz or bossa nova music for cocktail hour, and dance music for the reception. This may mean buying CDs or MP3s for a DJ or sheet music for a band. Be sure to include a chronologically and culturally diverse selection. The more people you can appeal to, the more you will be working.
Rehearse, rehearse, rehearse. A band will need to play through its entire song list many times to become comfortable and polished when playing.
Know your material. A DJ will need to become familiar with the tunes he has. He could easily have several thousand songs at his disposal. If he is not familiar will all of it, or if it is not logically organized, it is possible to play the wrong song at the wrong time and smear the company's reputation.
Organize a full run-through or "mock" wedding. Test out the full public-address, or PA, system, lights, smoke machine, and anything else that would be used in the act. Weddings are usually a few hours long, and every second must be perfect to get good referrals. Remember that the best advertising is word-of-mouth.
Let people know the band or DJ is open for business and that the act is high quality. The best way to do this (as well as maintain the group) is to organize a monthly showcase and invite as many people as possible. This is also a good place to get the initial photo and video footage necessary for advertising.
Implement the more traditional forms of advertising. Launch a website, print business cards, put together a promotional pamphlet and take out advertising space in wedding magazines. Be sure to include lots of photos and video where possible.
Network as much as possible. Get in touch with any other businesses connected with weddings. Good examples include catering services, florists, wedding venues, wedding planners and limousine services. Better yet, if a close friend or relative is getting married, offer them a great deal to get started. Be sure to take plenty of pictures of the bride and groom having the time of their lives!