These need to be clear, informative and unfussy, whether they are about your company or about a specific product or service. At the very least you want the receiver to read and/or keep them. Try to cram too much in and they will go straight into the bin along with the rest of the day’s junk mail.
You only have a matter of seconds to get past that first hurdle! Flyers and leaflets can be in any format from a single-page PDF attachment to a glossy, full-colour fold-out. The most important thing is to get the words right.