I do not think there is a tutorial on traits for Pharo users.
In O2, I wrote some commands that allow you to easily create and move
methods from a class to a trait. This is particularly handy when you
want to refactor your application.
With the book chapter I can get started (I knew about traits and composition possibilities before). I filled in the form on the bottom of the page with some comments, I hope they are helpful. Tell me when you want me to proof-read again.