When evaluating startups and ideas, David George who runs the @a16z growth fund gives this piece of advice: is the market demanding more of my product?
Truly unique products and companies don't have to 'sell' their product - it flies off the shelf. The market demands more. And those are good investments.
More advice and investment strategies from David on the latest episode: https://youtube.com/watch?v=eA9XDRz51Zg&t=2s