The type of text you have can make or break any design. These are need to know rules for applying text. From formal to personal all details matter, and with these rules you can put the final touches on your design.
"Vertical Landscape" by Eiko Ojala. It looks like a paper landscape but the artist actually works digitally and hand-draws all the elements to look like they're cut out of people. (Hint: the shadows help!
This book cover shows excellent figure ground/negative space. The contours formed by the position of the fox serve as the shape of a boy, I'm assuming "Peter." This empty space also creates a wonderful focal point for the book title to nestle into.