Whether you are making a brochure, or writing an unsolicited proposal, you can make it better by understanding the similarities and differences between them.
A brochure is a document about your products and services. They are often mass produced and given anonymously. Brochures come in a variety of shapes and sizes, and are usually printed in color with lots of graphics.
An unsolicited proposal is a document about your products and services. They are usually produced individually, and given to someone specific (although it may be to someone you do not know very well). They are often in letter form, unless they are large documents, in which case they are bound.
A sales letter is a short proposal and always includes a call to action. Depending on the circumstances, sales letters may or may not be given to specific individuals and are sometimes sent to people you don't know.
So what's the difference? It turns out that there really is not a lot of difference between them. All of them have to provide information and usually seek to persuade. Sometimes, the primary purpose of a brochure is to provide information. However, sometimes brochures that should persuade merely provide information. A key discriminator is whether the brochure has (or should have) a call to action. Marketing materials are almost always created to motivate the reader to do something. It could be to fill out a form, visit a store, make a purchase, visit a website, or to place a telephone call. If your brochure simply provides information, you should re-examine it to make sure it is persuasive, and consider re-designing it around a call to action.
If do you have a call to action, or something that you are trying to motivate the reader to do, then it may help to think of your brochure as an unsolicited proposal. The brochure should be designed to effectively persuade the reader to fulfill the call to action.
If you are writing an unsolicited proposal or a sales letter, you may not realize that it's not much different than a brochure with a call to action. Try focusing as much effort on graphics design as you put into a brochure when you create your next proposal. Every piece of copy, every aspect of the layout, and every graphic should contribute to persuading the reader.
Both brochures and unsolicited proposals tend to suffer from a lack of information about the reader. The more you know about the reader, the more persuasive you can be. However, brochures and unsolicited proposals are often given to people who you don't know very well, usually in the hope of getting to know them better. If the document is your first contact with a potential customer, your call to action will often be related to getting to know the reader better so that your follow up can be more persuasive.
All marketing materials can be made more effective when you know more about the reader. If the materials are not being sent to a specific individual, you should segment your distribution list into categories that are as specific as possible. If you are sending sufficient quantities, it is a good idea to test several approaches for effectiveness.
The next time you are preparing a brochure, unsolicited proposal, or a sales letter, take the time to think about it as if it was one of the others. Think about your brochure or sales letter as if it is an unsolicited proposal. Think about your unsolicited proposal as if it is a brochure or sales letter. Think about your sales letter as if it is a brochure or unsolicited proposal. Use the comparison to improve the document, but be clear about your goals and audience --- because that is what should ultimately drive the design of your marketing materials.