Andy brings up a good point: write the report for the intended audience.

Regardless of WHO you write the report for, you might want to write (and keep!) a full unabridged version for yourself for future reference. It's amazing how quickly one forgets details, and a full accounting of what you've done could be useful later.

There are textbooks out there for technical writing, which will give examples of various types of technical reports. Might be worth checking out.

Dennis