It is a professional honor to be invited to review a scientific manuscript as part of the peer review process. Please take this job seriously. The journal’s reputation depends in part on this peer review process.
Be critical. It is easier for an editor to overturn very critical comments than to overturn favorable comments.
Justify all criticisms by specific references to the text of the paper or to published literature. Vague criticisms are unhelpful.
Do not repeat information from the paper, such as the title and authors names, since this already appears elsewhere in the review form.
Check the Aims and Scope of the journal to ensure that your comments are in accordance with the journal policy.
Give a clear recommendation. Do not put “I will leave the decision to the editor” unless you are genuinely unsure of your recommendation.
Number your comments so that the authors can easily refer to them.
Be specific – refer to the line numbers in the paper or to the exact regions where you wish changes to occur.
Be careful not to identify yourself by your comments or by the file name of your report if you submit it as a Word file.
Read the abstract first to see if what the authors are stating makes logical sense, and if it is written in a way that is comprehensible. Some manuscripts involve excellent work and interesting observations, but they are so poorly written that it is difficult to understand what the author is saying. This is a relatively common problem with authors whose native language is not English. If the work reported in the manuscript looks interesting and/or valuable, the manuscript should be sent back for editing by a native English speaker or a professional translator.
Is the observation made and reported in the manuscript something new or is it work that reproduces previously made observations? Clearly, the more original the observation, the more likely that the manuscript should be accepted for publication.
Examine tables and figures to see if the legends are clear and if the tables and figures demonstrate the same thing that is stated in the text. Frequently, material placed in a table does not have to be reported in detail in the Results section of the manuscript.
Look to see if the statistical analysis seems to make sense.
Read the discussion and see if it makes sense and if it reflects what the data in the article report. Look for unnecessary conjecture or unfounded conclusions that are not based on the evidence presented.
Is the manuscript concise and well organized? Most of the manuscripts that I receive could be shortened with improvement.
Is the quality of the figures or photos adequate for accurate reproduction?
Subjectively, do you believe what the authors are telling you or do you suspect some consistent error in the hypothesis, methods, analysis of data, etc.? Is there some chance that there is scientific fraud or plagiarism involved in this manuscript?