I think the biggest mistake people tend to make is that they structure themselves too soon.
You look at “successful” companies and you somehow feel that their structure has been the cause of their success, and you should adopt their structure.
But it is actually the reverse. These companies built their structure as they grew; the structure was not the cause of their growth.
In terms of the structure and processes of an organization, you should be just a little bit ahead. In fact, barely 6–12 months ahead of your planned capacity of people, you should not build structure and processes for a 50-person organization when you are ten people.