Research the topic to clarify your claim and arguments and to gather supporting evidence. Look at opposing views so you can counter them. Go beyond a basic Internet search, and look for scholarly books and articles in library websites and databases. Select sources based on whether they are credible and seem respected and referred to by other people, not just because they agree with what you want to write.
Present the evidence in writing, and then make it clear why your claim is the correct interpretation of the evidence. Cite expert opinions and other research or data that supports your claim and interpretation.
Address counterarguments by explaining why they are not convincing. For example, their research may be flawed, or they may have been replaced by newer, more reliable results. The opposing side may lack evidence entirely or have logical flaws in its argument.
Include qualifications, acknowledging situations in which your claim does not hold true or limiting its application's scope. This helps to defuse potential counterarguments and strengthen your credibility. You can take this measure earlier in the process if that makes more sense in your argument.
Summarize your claim and the main supporting points to ensure readers end the report understanding exactly what you argued and why it makes sense. If you urge readers to take action, make that one of your last points.
Test your argument by having someone read your report. Determine whether or not that person understands it as you intended and if she is convinced. If not, find out why not, and make changes in the report to address that weakness in the argument.