Perceptual training has been shown to be an effective and rapid way of training people to make simple diagnoses using medical images. However, it appears to be less effective at training people to make more complex diagnoses that require non-binary judgements. In the present study, we investigated whether perceptual training could be augmented to make it more effective and what factors limited its effectiveness. In Experiment 1, we created artificial stimuli that were designed to simulate liver ultrasound images to assess perceptual learning for a complex task that involved judgements on a 7-point scale. Whilst performance improved somewhat with training, we found that incorporating annotations into the training provided no benefits. Additionally, contrary to our expectations, training that was structured in a stepped fashion was detrimental to learning. In Experiment 2, we found that perceptual learning in a simple task with shaded disks was most impacted by the extent to which the brightness levels of each disk were discriminable but that attending to multiple locations did not result in a significant cost to performance. Our findings show that augmenting perceptual training does not increase learning and that learning is less when the relevant features are harder to discriminate.