Make a clear and direct subject. You need to synthesise your activity, business or event in a couple of words. And these words should punch right on the face of your client. For instance, if you are going to do a yard sale, use “BIG SALE!” or “YARD SALE” or “GARAGE SALE” according how is the common use in your town. If your intention is to make your brand to be known, use your name and logo very big.
Use BOLD and CAPITAL HEADLINE. Remember that flyers usually receive a glimpse from the clients, so you need to give your message in that brief moment. So a big, clear, bold and capital letter typografy is the best option.
Use the flyers as a coupon. You can make they keep the flyers by making a discount coupon or another valuable use, as a number for a raffle. This can make the flyer stay much longer in client posession, and even change of hand, creating new clients, if the original customer thinks in another person for that discount.
Make some tests. Once you have a prototype of the flyer, use your friends or customers you know to they give some thoughts. Here are some questions you can do: “Is it clear or confuse?” “What do you think this flyer is about?”. When you hear the right answers, then the flyer is ready to spread its wings.