While it is critical to have actually done the research, you must also clearly communicate this fact to your reader. Your content should signal the reliability of your information so that readers see that your conclusions are trustworthy and well founded.

You should bring the reader with you on your journey: show them how your data came together, how your conclusions follow from the data, what the limitations of your study are, and where to look for more information and context.

Make sure your text is complete and comprehensive. Think about what readers will want to know and what questions will follow from points you are making, then answer those questions. If you avoid tackling obvious topics or questions, the text will lose credibility (or worse, your reader might think you are trying to hide something and become cynical of your motives).  

Show your research. Support from many respected sources lends credibility to your text. These sources can include data (presented in tables or other graphics), specialist research and opinions, academic papers, case studies, relevant examples, and many other sources. Show your readers the basis for your conclusions by making the inputs visible.

Qualitative assessments, such as critiques and opinions on literature or other humanities subjects, will be significantly more persuasive if backed up with strong supporting information and examples.

Present your sources clearly. Explicitly discuss the foundation of your information, opinions and conclusions – studies, academic papers, surveys, specialist opinions and so on. Use a consistent referencing style and include comprehensive information so readers can check your sources if they want to.