IMO best way to learn is to see how someone else did it. If you have a favourite follower mod just pull it apart :hehe:
I agree with this. The vanilla followers are a great place to start to get an idea of how the basic structure of what you will need works (object script, a few packages and some dialogue to keep that all running and to add flavor), but they lack an awful lot. Vanilla followers don't even have sandboxing packages. Plus, different modders do things differently. You'll learn a lot looking through other mods. Although it may be confusing at first.