Stay focused and don't try to do too many things at once. Care about execution quality.
Growth solves (nearly) all problems
You want to sound crazy, but you want to actually be right.
I think as a rough estimate, you should aim to give about 10% of the company to the first 10 employees.
As you grow, the productivity I think, goes down with the square of the number of employees if you don't make an effort.
The single word that matters most I think to keep the company productive as it grows is alignment.