Diagnostic errors are the most common, costly and dangerous of medical mistakes. In part 1 of this series, we described how general and dermatology-specific cognitive and perceptual biases underlie most of our correct diagnoses, as well as being a source of diagnostic medical errors. In this second part of the series, we describe some tactics to combat diagnostic error. Metacognition, or thinking about how we think, is the central approach advocated to avoid errors of 'uncritical' diagnostic thinking. Current individual and medical cultural attitudes need to be modified in order to incorporate improvements in diagnosis. Algorithms, artificial intelligence and system changes are being developed to address error and improve diagnostic accuracy.