For some time now, the Video games project and the Military history project have been cross listing their articles undergoing peer review in an effort to improve the quality of articles, as well as the copy editing skills of editors. The idea was first proposed by User:Krator as a way to better prepare articles for Featured article candidacy. After being approved by both projects, the idea was implemented under a trial period, and eventually approved as a standard practice.
New, cross listed military history articles are announced on the Video games project talk page, and listed on the Video games Peer review page under a special section. Video game editors are encouraged to leave any type of comments that come to mind. If you don't know anything about military history, that's perfectly fine because that's the point. An editor lacking knowledge about the particular topic can provide a helpful point of view as a general reader—the intended audience.
A peer review process such as this will not work if editors do not give as well as take.
Peer reviews are meant to examine not just the prose, but the sources and images used in the article.
Feedback can range from brief comments after skimming through a page to a full blown dissection of grammar, structure, and references. Either way, every bit helps.
Reviewing another editor's article can help sharpen your writing skills, which in turn can improve the articles you write.