Content is more important, as per usual. As for the structure of the report itself, I'd go
Executive Summary (write last)
Body (usually involves assessing the current business situation in some way and identifying key concerns and problem areas)
Recommendations (this is important - many questions ask for recommendations, and even if a question doesn't specifically ask for them, if you can pace yourself well enough, put them in, because it shows the marker that you're capable of synthesising all the stuff you learned into a cohesive set of possible solutions for a particular problem)
Conclusion