You have to be decisive. Indecisiveness is a startup killer.

When it comes to starting startups, in many ways, it's easier to start a hard startup than an easy startup.

The hard part is that this is a very fine line. There's right on one side of it, and crazy on the other.

When lack of structure fails, it fails all at once. What works totally fine from 0-20 employees, is disastrous at 30.

One of the pieces of advice that we give at YC is: try to work together on a project rather than just doing an interview.

Remember that the idea will expand, and become more ambitious as you go.

As the company grows and about this 25 or so employee size, your main job shifts from building a great product to building a great company.