For early employees you want people that have somewhat of a risk-taking attitude.
Obsess about the quality of the product.
So if you want a culture where people work hard, & pay attention to detail, focus on the customer, are frugal: you have to do it yourself.
The single word that matters most I think to keep the company productive as it grows is alignment.
No matter what you choose, build stuff and be around smart people.
Before product/market fit, your only job that matters is to build a great product.