Plan Summary At End of Report
Soon after you are finished with your report or project, write executive summary straightway. It is likely that you can better give all information in the summary because the entire report facts and details are fresh in your mind.
List Topics/Chapter Headlines
You should provide each chapter headline in a declarative manner and then write description in one or more than one paragraphs. This will help you better approach to your summary project.
Include All Support Details
Avoid giving vague details or discussing matters halfway through. You have to write your sentences and paragraphs that make a sense to reader. Summary is not something bases on a sentence here and there, all information should make sense.
Formatting and Errors
An executive summary formatting is as important as formatting of the entire report. You can follow a certain template or pattern but format it properly. Also check for errors in the language etc.
You can ask some one senior in your office to have a go at the summary, and then work out on shortcomings in the light of their advice. They can even spot some minor mistakes and recommend you changes needed.
Be Sure of Your Work
Read the summary after completion and see if it makes sense to you. If you are convinced that the summary provides all the information that a fresh reader would like to know about the report then should think your effort was worth made.