Banner Design Dos & Don'ts
T E X T
DO Keep Your Message Short
Simple banners have higher CTRs than wordy or gaudy banners. If your text takes more than two seconds to read, you've got too many words. If you can do it it one word ... or no text at all ... so much the better. When there's no way to find a graphical representation of the message, always use the lowest word and letter count while still communicating your intended message.
DON'T Force It
Though it may be tempting, avoid using a smaller font size just to fit more words into the banner.
DO Make Your Text Legible
For a quick read, choose a highly legible font face and type size. Make sure type color contrasts heavily with the background color. And allow adequate kerning (leave plenty of space around each letter).
DON'T Run Text To Edges
Unless there's a certain effect you're going for, allow some space around the text so it can "breathe".
DON'T Cram Lines Together
When using multiple lines of text, inadequate leading (space between lines) makes text more difficult to read.
DO Consider Aliasing and Antialiasing
Antialiased text and graphic edges are smooth and slightly blurred. Though antialiasing requires extra colors, it eliminates the jagged appearance of diagonal and curved edges as seen in aliased type. Banner optimization can make antialiased type uglier that aliased type if there aren't enough colors in the optimized palette to retain the smooth edges. So in some cases, you may want to go with aliased type or graphics to reduce the colors in your banner, especially animated banners.