In developing your marketing plan, it is important to clearly define those core services you want to market and your target audience. Identifying a particular market and offering that market a specialized service is the definition of niche marketing. It doesn't matter whether its the restaurant industry or the health care profession, by offering a service that fills a particular need for a particular audience you can open up a new potential market, with ready-made prospects.
The key to success is to avoid a one-size-fits-all marketing strategy and to target specific markets with particular services. You can break down that market according to any set of criteria, whether its income level, demographics, industry, specialization, or even specific hobbies. The more you know about the audience, the more you can target your marketing efforts.