The centre part of any business web template has to be kept for showing off products or services. In the centre if there is a place the products or service with little description the users can easily understand what type of business you are running or what they can get from your site. So it is necessary that the layouts give you scope to utilize the space for attracting your visitors cum customers.
The Details are important _ Pay special attention to the details. They affect your readers very much. Details like alignment of the texts and the number of lines which your paragraphs include, can make readers bored or can interest them. Try not to make your paragraphs longer than 3 or 4 lines. When your paragraphs are short, people will read them easily. But if they are long, it will seem overwhelming to people. The colors you use in your newsletter design is important as well. So you should know a little about colors psychology. It's not hard. You must already know about the effect of every color on people, before designing or choosing your newsletter template.