1. Organization skills/project management skills: ability to pull together internal/external resources, ability to create clear plans, ability to build relationships with other teams to make cross-team collaboration easier
2. Communication skills: ability to deescalate and mediate conflicts fairly, ability to give both positive and negative feedback regularly, ability to create psychological safety, ability to deliver bad news while maintaining psychological safety, ability to run efficient meetings, ability to make unpopular decisions while still commanding the team's respect, ability to engage with different personality types and communication styles
3. Delegation skills: ability to translate ambiguous directives from above into actionable tasks for the team, ability to arrange tasks so that individuals have the creative freedom to figure out how to do it, predictability in decision-making, ability to shield team from external pressure, ability to give negative feedback immediately, ability to fire low performers before they fester into team morale and culture problems
4. Coaching skills: ability to give targeted advice, ability to match employee's own aspirations and growth objectives to projects, enough technical expertise to point people in the right direction, ability to evaluate skills and hire for them
They also often take theory. If you’re reading this and trying to learn more about management, don’t shy away from taking some time to read good books which teach about the theory of, say, how to be good at feedback.
Someone who brings their team achievable goals, and the resources they need, and then gets the hell out of their way.
Someone who encourages leadership (in all its many forms) to come from within the team, and doesn't see it as a challenge to their authority.
Someone who understands that respect is not magically granted by position.
Someone willing to make decisions - sometimes tough ones - on behalf of the team, to communicate both with and on behalf of the team, and defend the team's integrity and autonomy.
Someone who understands that communication starts with listening.
I think the full answer to your question would deserve at least blog post ;-)
Get those right and everything else will follow. So simple but only a fraction of managers get it.
1. Create a continuous feedback loop with every single person on your team. This is why 1-1 meetings are extremely helpful.
2. Understand where each person on your team wants to go (career goals). Do they want to become X in 2 years? Do they even want to work in tech at all? Find ways to help them get there.
3. Document all the important conversations you have. Share it with the person. Most miscommunication happens when you talk about something and it's interpreted in various ways. Documenting these conversations and sharing them helps cut down on this.
4. Act like you care about them as a person.
This seems like the answer to the first line question of "how do I scale an engineering organization?" but you are not at an addressable solution yet. It's valuable but not sufficient.