One subject that doesn’t get enough attention in marketing is readability.
There’s not much point in using cool looking fonts or design if the copy ends up being hard to read. People will just skip it.
A few basic rules:
1. Serif fonts are easier to read than sans serif, unless you are dealing with very tiny print or low resolution (as in non-HD TV).
2. Standard capitalization is easier to read than ALL IN CAPS or other non-standard capitalization.
3. Black on white or dark on light is easier to read than reversed lettering such as white on black.
4. Regardless of color, low contrast of text to background makes it hard to read. A medium Blue against a medium Red shade for example.
5. Older people need more contrast and larger type sizes than younger folk! If you are younger, the fact that it is easy for you to read doesn’t mean it is going to be so for a lot of your viewers / readers.
6. Anything other than standard left-to-right text is going to be harder to read (such as vertical or following a curve).
There’s more to readability, but this will help avoid the worst errors.