Hi Steven,
I do one on one training with my colleagues. I train the Editors differently from how I would train our Events, Administrative and marketing department. The other teams do not need to know the admin set up, lead scoring, data management, and template creation.
Our events (I set up the programs and templates for one of their events and walk them through how to set up the other events from start to end) and marketing department do need to know more about the automation. In my marketing department I set up a Marketing Communications blog for Marketo/SFDC best practices. This has been very helpful for us. One of the first things I posted was an illustration of our lead lifecycle model (this is important for everyone in Marketing because none come from a Marketing background except for me and my boss), lead and demographic scoring (in the works), program/campaign results (to see what's what's working or not), archiving campaigns best practices, pre-flight checks, A/B and multivariate test results (in progress), and analytics. I have to mentor one other person in my team and I'm going to make her take notes and archive, or I might do a video capture of our training, so she'l have something to refer to.