My fellow MVP for Visio, and author, and friend, Scott Helmers, has recently presented a series of videos entitled “Becoming a Visio 2013 Power User”. Scott is a natural presenter, and he does a great job in getting the fundamentals across.
There are two ways that I know of to see these videos:
Microsoft Virtual Academy : http://www.microsoftvirtualacademy.com/training-courses/becoming-a-visio-2013-power-user
Channel 9 : http://channel9.msdn.com/Search?term=Becoming%20a%20Visio%202013%20Power%20User#lang-en=en&ch9Search
Highly recommended.
Scott also patrols Experts Exchange : http://www.experts-exchange.com/Software/Office_Productivity/Office_Suites/MS_Office/Visio/