What is relevant and useful content?
A good newsletter provides content that your target audience can use. For example, if your business is in home décor, your target audience can use advice on mixing and matching fabric, textures, and colors. Or, they can use information on the latest trends in décor. Perhaps you can show them how to give their family room a makeover using products and supplies found at your store. On the other hand, telling them the history of your business, although it may be of interest, is information that your target audience can do little with.