An idea I love from "The Personal MBA" is that a manager is merely an assistant to the team that does the heavy lifting.

A successful project management is required to be a great communicator and plan according to the team, requirements and various milestones for the project.

Agile is a great methodology that provides some quick iterations, providing you with the opportunity to adjust the project on the fly, notice delays during the project and fine tuning the process so that it meets the end goal. From a "roadmap management" perspective you need to break the assignment into small chunks and delegate them to the right people, manage the time line in a reasonable and slightly pessimistic way, and figure out all of the possible bottlenecks that could go south (i.e. risk management).

From a "team management" perspective it's all about communication, understanding your team members, their skills, their pros and cons. You have to be able to delegate the right assignments to each team member based on their strong skills, expertise and work process. You have to deal with the team dynamics, make sure the burnout levels are extremely low, and implement a communication structure that ensures that everything is clear, the team is on track, the team is productive, there are no obstacles, missing dependencies, or internal issues that should be taken care of.

You have to be the principal conductor for your team - balancing the work load from both project and team perspective, solving internal challenges and keeping the team spirit high.