Peer review is one of the pillars of science, but let’s be honest, most of us have read reviews that range from clueless to petty to outright destructive. From sloppy reviews that give no real criticism, to overzealous brainstorming sessions listing every possible experiment under the sun, the spectrum of bad reviewing is wide. If you're going to spend your precious time reviewing a paper, here’s how to do it right and efficiently.