You don't get to make their decisions but you do get to choose the decision makers.
The biggest PR hack you can do, is not hire a PR firm.
The natural state of a start-up is to die; most start-ups require multiple miracles in their early days to escape this fate.
You certainly don't need to have everything figured out in the path from here to world domination.
The best people know that they should join a rocketship.
No growth hack, brilliant marketing idea, or sales team can save you long term if you don't have a sufficiently good product.