Momentum and growth are the lifeblood of startups. This is probably in the top three secrets of executing well.
Obsess about the quality of the product.
Keep salaries low and equity high. Keep the organization as flat as you can.
I think the best thing you can do is be aware that as a first time founder you are likely to be a very bad manager.
Cofounder relationships are among the most important in the entire company.
I prefer to invest in a company that's going after a small but rapidly growing market than a big but slow growing one.