The book cover should clearly bear the two core messages of the book: University education and Germany. Both of these themes should be clearly recognisable on first sight when looking at the cover.
The rest of the design I will leave up to you and your imagination.
One note: It should be distinct from other websites about the topic, particularly the following two:
So if you use logos or graphics, please avoid using anything that looks like the logos on the front page of those websites.
For the dimensions and the guidelines that the cover needs to be in, please see the points "File Types", "Dimensions", "Size", and "Color" here:
The title of the book is "Studying In Germany For Free". The subtitle is "The complete A-Z Guide to Free Education in Germany".
The book cover should also bear the name of the author "Adrian Winter". (subject to change)