No start NoComm: Diag Approach (Nissan Rogue)

A local shop called me in for a diagnosis on this 2012 Nissan Rogue. The owner tried fixing the blower motor, and now the car won't even start! There are many directions you can take on a car where almost nothing works.... However, what is the MOST EFFICIENT DIAGNOSTIC APPROACH?? Share your thoughts in the comments! Enjoy! Ivan