PowerPivotPro offers some thoughts on The Ideal PowerPivot Professional: How to Hire, Grow, or Become One « PowerPivotPro. Many of these ideas apply to GP professionals as well.
The Ideal PowerPivot Professional: How to Hire, Grow, or Become One « PowerPivotPro
Excel & OfficeTips & Hidden Features
Archived post from 2013. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.