Absolutely agree that this should exist. This is a perfect opportunity for us to have a session with the goal of defining a set of tips to help people get started.
From my experience the overarching recommendation I would make is to pick a project that could benefit from community management and do it in an organic way. What I mean by this is picking a set of areas to improve without trying to dominate the community.
For example, this could be improving advocacy docs, running more meetings, creating local user groups, helping with governance etc. Get a couple of wins in first and start growing your reputation. Open Source is generally mertitocratic, so relationship development is critical.