Karaoke singing has become wildly popular in the past decade and to back this statement up, look no further than your own community. I'm sure there's a local karaoke club or karaoke singing night at a bar or club. The requirements for starting a karaoke DJ service are basic: You need karaoke equipment, a good music selection, and reliable transportation. Of course a fairly decent singing voice and a dynamic personality isn't going to hurt business either. You can market your service to event and wedding planners as well as to local nightclubs, restaurants and pubs that may entertain the idea of a weekly karaoke singing event or contest.
Your main customers are the venues that will host your karaoke services. This can include bars, restaurants and clubs. Don't forget less-visible lounges like those in bowling alleys, hotels and restaurants. You can also market your service to planners of events like corporate meetings, holiday parties, weddings and birthdays. Your secondary customers are the karaoke singers; you've got to provide a great selection of songs and good service to keep them coming back week after week. Usually, tips will also be part of your business income so it pays to be friendly, fun and helpful.
You need a professional-level karaoke system, which may include a karaoke machine, microphones and speakers. (The last item is a must if you're marketing to venues that don't have speakers you can plug into.) You will also need monitors so that participants can read the lyrics, a very large catalog of CD-Gs (karaoke discs that include the graphics that appear on monitors), and a way for people to look through the songs--alphabetic lists by artist and song title in three-ring binders usually do the trick.