Above: Here are two progressions of the front cover. They both have calm, relaxing blue borders. The right image has a line graph going through it, subtly suggesting a form of progression.
This is a simple and basic design- uncluttered and relaxing/enjoyable to look at.
Below: I made use of the cheesy covers of a Professor in Human Activity smiling and offering you help. They all look pretty 1990’s so I applied this too. For ultimate cheese, a starry bubble! I think it works really well in terms of mocking Self-Help books but I don’t think that it’s obvious enough that it is mocking them and not just another one of them..