You should be a developer, and a good one.
2) Release Management
Your main job is to resolve needs and roadblocks (not to make sure that people are following any methodology).
3) Product Management
Prioritize, that's all. Then, you just have to work on the most important tasks from your list (which will also be small ones if you did your homework).
Learn how to test people inside your team.
5) Managing People
Be honest and helpful.