If people have bothered to write or express an interest in your brochure, they are prospects for the product or service you are selling. Tell them everything they need to know. Spotlight the important facts. Graphic devices can help to spotlight important information. Use photo's instead of drawings.
Photographs suggest reality in the readers mind.
Make your brochure worth keeping. Give your piece longer life, and longer selling power, by encouraging the consumer to keep it handy. Give your product a first-class ticket. Make it as good as your finances will allow. Ask for the order.