Compile all of your facts and write an outline for your report. The outline is the bare bones of your report, and it should list the subjects you're going to cover, starting with the Introduction, moving through the body, and ending at the conclusion. Once you have the outline worked out, you can begin writing your fitness report.
Write the report, following the steps you put in your outline. For instance, if your report concerns the standards of physical fitness in the military and the number of individuals who meet it, begin by laying out what those standards are in your introduction. As you write, use adjectives appropriate to your report. For instance, when you're describing how many soldiers are fit, use a number because in this case that number is an adjective. Don't use needless adjectives, but rather use them to make a point. If your report reveals that a particular standard is too difficult to accomplish, you might refer to the exercise as "grueling" rather than "intensely difficult."
Have someone read over your report and provide you feedback. If some of your descriptions are vague or confusing, then use more specific words. If you say that "fitness standards seem to be improving in the armed forces," you could edit that by giving numbers to back up the statement, making it more specific to your report. Once you're satisfied that you've finished your report, hand it in.