The basic Newsletter

First of all is a basic newsletter. No oversell just general items of interest, events, specials etc.
This is the customer touch that we must maintain and build on

Not to long, lots of visual aids and a soft call to action at the end.

An example.
A signwriter sends out a monthly Newsletter showing the latest car wrap or Large building sign. I might not buy this month but eventually when I am ready he will be my first point of contact. As a by product he is advertising for his client in the mail.

I send to my base Items of interest to small business that I gather from Google.

A Carpet store sends stories on new installations and new products used.

Then there is Target marketing

Target marketing.

Where you have new products, special Pricing limited supply type situations.

Segregate your audience

Only send marketing material to interested buyers by segregating them in groups.
Those that will buy General Motors products away from Ford Buyers as an example.