Visit bookstores, your library, or go to the internet and research as many book cover designs as possible.
You learn as much from badly designed books as from beautifully designed books.
In the Western world people read from left to right, top to bottom.
Position your text and image in appropriate levels of importance.
Put your title in the top half of your cover.
Avoid centering all the text on your cover or title page, this looks pretty unprofessional.
Right or left aligning creates much cleaner lines. Never use more than three different fonts on your cover, to not confuse your reader – this includes bold, italic or underline variations.
Use bold or complementary colors, but NEVER use a white or a very light background. Use light font on dark background for dramatic effects (novels, spiritual, etc.) and dark on light for easy readability (self-help, how-to, business books).
The elements should be clean, not cluttered and the font easily readable, the text balanced in size and style to the graphics. Allow at least 0.5″ in from the trim guides to place all your elements. This will ensure enough allowance around the cover’s edge and provide a more tailored look.
Give your finished cover the thumbnail test. Your front cover image should look crisp and polished when reduced to post stamp-size for display on online bookstores like Amazon.