When looking at book cover designs the typography is usually placed either near the top or bottom areas of the cover, not usually placed in the middle but it is only mainly placed in the middle when there is no sort of design or pictures on the cover.
The text that is normally used for the title is usually in a larger font size than the author’s name. The smallest font size that is normally used in book covers is normally used and applied to either quotes or “best seller” etc and the author’s name is usually the second largest font size at the top or at the bottom of the design.
The main layout of imagery is also varied as normally they can either fill the whole cover or they are placed in frame that’s usually at the bottom of the cover, with the text positioned above and slightly on the image. Also the main design is usually a photo of something or a illustrative piece. Photography is a great way to get the perfect design for the cover and sometimes designers edits those photos to become a silhouette of something.
Most cover designs is normally edited in illustrator and using this you can create a quick and easy design that suits well for all people and then you got photoshop for where you can use it to create a over-desgined cover that would look cool and interesting for people to look at which would attract people to read it.
In my design i used photoshop so that i can create a cool cover that is interesting to look at.