These are some nice examples for tracking breakdown. Most of these shots used mocha tracking and also they have used masking with more than one or many layers of tracking. It is tricky to use many layers of tracking, and also masking in mocha is something interesting that you can mask your layers, or you can also use it to actually track on specific area and ignore the masked area. This trick can help to track very complicated areas, or a footage that has many details that confuse tracking in mocha.
This is a nice example of multi layer tracking and masking in mocha, but unfortunately it is in German language, though if you are into mocha you should be able to pick up the basics he does in this example. I tried and learned some bits from this, though my German language is not that bad.