In any industry there are many marketing niches, defined by WHAT you sell and WHO you sell it to.
Sometimes business owners think they will be losing out on a lot of potential business - if they narrow their target market or what they are selling.
The opposite is almost always true. There is usually plenty of business even in a relatively narrow niche. By concentrating, you can get much more specific in your marketing. That is usually what people are looking for - someone who SPECIALIZES.
Do you know what your niche is?