Here's a little demo video that I put together to explain pushing/pulling with multiple remotes and how tracking branches make this easier. It's one of the chapters from my "Git Adventures" talk, but it didn't make it in to the talk in Amsterdam last week since we chose a different adventure that time - sharing it here in case it's helpful to anyone else, and so I can find it later!

I also blogged about the tracking branches in a bit more detail if you're interested.