[greenyoda]

If you end up with a team of 20 people, there's no way you can manage them all yourself. I think the most important skills are to be able to:

1. Hire technical leads and managers to manage groups of people (or promote from within your team, if you have people who can and want to do this).

2. Delegate full responsibility to them for their teams' outcomes - don't try to micromanage their teams.

As a manager of managers, don't expect to be able to spend a lot of time doing hands-on technical work. And just because you're a good developer or technical lead doesn't mean that you'll be a good manager, or will like managing. After years of being a manager, I went back to being a developer.