Serious answer?
I would go EXTREEME MICRO NICHE...
Shoot my OWN exclusive content, then make it available online on a PPV basis... The videos would NOT be downloadable. The pics WOULD be downloadable, as part of a 'freebie' for those PAYING to view the video online.
Videos would NOT be watermarked. Pics would be HEAVILY Watermarked...
I would NOT use an affiliate model, but I would monetize the payment methods across the broadest range possible. Id have full geo pages in diff languages and allow credit card, SMS TEXT, Payment by phone and everything else on the market I could...
(Not having to worry about affiliate tracking would free me up to accept payments HOWEVER I want... Even via the post!)
I would sell at premium price and encourage the watermarked pics to be shared, as a method of advertising within the community of the chosen niche...
The above is just a generalization. I have much more specific details... But thats cause Im actually doing this RIGHT NOW !
I'm not 'Starting From Scratch' overall... But I am starting this project from scratch at the moment !