Decide which kind of report you're writing. Business reports, research papers, technical reports, book reports all differ in what content must be included in them.
Research the subject. Researching allows you to include even more information than you already knew about the subject. Researching also lends a hand when it comes time to include reference material.
Outline a rough draft. Outlining gives you the basic structure of a report and provides you with the main points needed to complete the report.
Create a thorough structure. The structure of a report contains the most important parts of the report: title, introduction, body and conclusion. The introduction and body must introduce and expand on the main objective of your report, while the conclusion ties up everything you've said.
Stay on topic. Jumping from one thought to another in a report doesn't allow the reader to fully understand what you're trying to present. Making the reader wade through a sea of off-topic paragraphs and sentences weakens your report.
Revise and rewrite. First drafts normally contain a litany of mistakes. Revising and rewriting allows you to polish the report.