Diet, fitness, disease
Make money, investing, biz-op,
Find love, dating, get love back,
Health/Wealth, Health/Relationships, Wealth/Relationships
Evaluate your core product idea and see what the connection is to one of these three main areas. Other areas can work but the three main interests are ones that are universal. Because of that universal nature you will need to niche down pretty far to find some blue ocean. But a goal is to keep segmenting until you find the blue ocean and then throw rocks at the red ocean. Position yourself as NOT the red ocean, make that a core part of your message.
The product needs to have one central and big idea, a recurring thought that rides through all of your marketing messages. It is the USP of the product. You can have several hooks to get attention on the product but the core product should have a single USP.