It's the same as it's always been: build something people want and acquire customers.

> I think it would need the backing of something like ycombinator, techcrunch or techstars

That's a bad mindset, imo, and probably just a distraction. If it's such a great idea that you think it is, build it and acquire users.

I think it's worth glancing at https://www.ycombinator.com/resources/ - but I think more people use this as an alternative to building things and getting users.