Visual tender is the first step, the online sale. The people have a high scan a Web page to read quickly, especially on a website. It is important to build on this aspect by a large visual stimulus. E-Book cover art has a long way in the last 5 years. Graphics with high density can make dealing with your product, marking with a high degree of professionalism and credibility.
In my research in the best design tools, I discovered that the adage "you can find what you pay for" holds all too real with the cover. Here is a report of my findings. It is divided into two categories: (1) software, and (2) of design.
Software / models
If you do a Google search on the e-book is really only a few products sold in the first search results pages.