All of the above. Prove your team is credible and your idea is solid and the only thing holding you back is the money. Even if you don't have the capital to build the full-scale thing, you can still make a lot of progress on the cheap: conduct research, model your business, test components, do user testing, get LOIs from customers, line up your first few hires, and so on.

Not OP, but the slides here give a really great answer to that question: https://www.codingvc.com/saastr-2017