"Obviously there's a diminishing return if you hit specialization of 'There's one business in my region I can market to' -- how do you know when you've specialized enough"
Know your target market, like EcommerceKnow niches within your target market, like Women's Fashion and Beauty or Every Day CarryIdentify if there are 20-50 companies in your niche in your target marketIdentify if of those 20-50 there are 15-20 companies that are paying for consultants, have paid for consultants, or are looking for
help solving a problem
Iterate. Too many companies come out? Become a
little more specialized, based on your research. Too few? Become a
little less specialized ("SEO optimization for women's fashion and
beauty stores selling $1,000,000/yr and based in New York" →
potentially too specialized)