Consider who you are writing for? Examples:
For the following report template we divide the report in logical parts, each consisting of one or several chapters or sections. In the real report there are only chapters.
(The beginning:)
Title and authors
Abstract (e.g. one paragraph each):
Preface (Only in ambitious texts). People you thank etc. You can also put a short acknowledgement at the end of the report.)
Table of contents (only for long reports)
(The problem, background, and prerequisites:)
1 Introduction (not too long, this is the first real chapter of the report) short background, purpose, description of the problem, related work
Background (if necessary). Background knowledge, prerequisites, notation, perhaps a more detailed problem description. Could be split into several chapters or at least subsections.
(Your work:)
This part typically constists of several chapters presenting your work and solution method in some good way.
The problem and background part should not be too long, so that this comes too late in the report.
(Results and conclusion:)
Results. Runs for different problems, comparison with other methods, your interpretation
Conclusions. Short summary of what you achieved, discussion, reflection, experiences, further work
(Additional material:)
References
Appendices (if necessary). Program code, specifications, manuals, extensive data and result tables...
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Remember that for those who do not have the time to read the whole text, it should be possible to get the most out of reading:
Always adapt these templates to your specific project! Makre sure that the names of the chapters and subchapters are correct and informative.