Expand on Your Efforts

Once you have provided a way for 'dog lovers' to find organic products for dogs, you need to go to the next step...and expand your efforts.
If dog lovers want to find these products, you can be assured that cat lovers are no less passionate about their pets.
Using the same procedures given in the inital example of niche/ sub-niche marketing, do the same thing for cats.

You may find it necessary to use some of your original affiliate product programs...if they provide products for cats too...but, you need to focus your marketing efforts toward the 'lover of cats'.

This establishes yourself as, 'something of an expert', in the field of 'organic products for pets'...and you can link your sites, to give a further boost to your Google search rankings. And don't just stop with, cats and dogs....are there other pets that need 'organic products' for their well-being?

Then...you may want to go a bit deeper and...sub/niche your sub/niches. By that I mean, focus a new site just on 'Organic Dog Foods'....another new site just on....'Organic Cat Foods'...and yet another on just 'Organic Pet Grooming Products'.

You see where I'm going with this....I'm sure.

This is the true 'secret' of Niche Marketing. You don't get just one niche...sub/niche and expect to 'grow' that...it will surely 'flat line' in time....but, if you cover ALL Aspects of 'Organic Products for Pets'...generally, at first...and then 'in-depth'....you'll almost certainly have a 'winning niche' on your hands...if you work at it.

You may have changed your main niche from...Dog Owners to Pet Owners....but, it might bring you in a very nice little income in the long run. Who knows, once you've done all this learning on the subject, you might have enough material to write and sell your own books on the subject...that's kind of how this niche thing works out.