I use 4 basic ingredients in our newsletter.
-personal message ( This can be about your family, an up an coming employee, special training, cudos for someone, awards, etc.)
-an detailed article about a maintenance service you provide or an install. (This will set you up as a expert in your clients minds. It should be relevant to the time of year. It also sharpens your own knowledge. Anytime you study a topic in order to teach it, you learn more.)
-happy Mueller customers. (I use a survey twice a year to get feedback from our clients. I get permission to quote them and will use their quotes in the newsletter along with their names. People love to see their names in print and hear real life qoutes.
-a list of our services, (Along with the detailed article, the list of services is an upsell tool. It makes sense to have it there but doesn't come across as an advertizement.)
The rest is graphics, historical quotes, mission statement, pictures etc.