Below are some all too commonly problems that you might encounter, and some tips on how to address them.
Recommended action: resolve the contradiction by making a clear recommendation that helps the author address the underlying concerns in a manner that improves the quality of the manuscript; often it is possible to get to the underlying issue and create a recommendation that effectively eliminates the contradictory comments; sometimes it is necessary to side with one of the reviewers
Recommended action: contradictory reviews are not a bug, they are a feature - such contradictions allow us to identify contentious issues and differences in perspective; help the authors navigate this conflict by using the same guidelines as for contradictory comments: make clear recommendations that help the author address underlying concerns in a manner that improves the quality of the manuscript; help the author address the underlying issue and create a recommendation that helps the authors to reduce the chance of adversarial responses to their work; oftentimes this can be achieved by explicitly acknowledging unresolved issues or differing perspectives; encourage authors to resist the temptation to placate by removing or softening statements that might cause discussions
The review is too vague, contains mainly musing instead of actionable recommendations
Recommended action: whenever possible, turn comments that contain valuable insights into actionable recommendations; help the authors navigate vague comments by explicitly stating which comments require no action from the authors; if the review contains no useful content, rescind it and give the reviewer a low score using the ScholarOne function for evaluating reviews.
The review is insulting the authors, off topic, biased towards a particular interpretation, making the best the enemy of the good, trying to take over the manuscript as a co-author, etc.
Recommended action: follow the advice for creating an inclusive and positive peer review experience by helping the associate editor redact counterproductive and unprofessional comments. In your recommendation to the editor,
point out any comments that need to be redacted
if any of these comments have scientific merit, please suggest language that the associate editor can include in their letter to the authors to share any useful aspects of the redacted comments in the guise of comments by the editor