Using DAX studio to create PowerPivot measures
The newly released DAX studio is an excellent tool to develop and troubleshoot DAX calculations as it provides a way to visualize tables as they are internally represented during the computation.
The more advanced your DAX calculations, the more you will need to use intermediate 'filtered tables' in order to arrive to a specific output, and this tool allows you to better understand how your filtering actions are being applied across the tables and rows that become active during the evaluation of the expression.