Here's a great quote by British author C.S. Lewis:
In letter writing one ought to know when and where the other person reads, as it makes more of a semblance to real conversation.
Lewis wasn't talking about direct mail, but about real letters between one person and another. (Remember that?)
But his advice is good for those of us who write to donors: Always have a mental picture of the person you're writing to. That's right -- one person. You're never writing to a large audience. The person you visualize should be "demographically correct" -- most likely an elderly woman.
Imagine what she thinks and believes -- not what you want her to think, but what she really does think.
Picture the context she's reading your message in. A crowded in-box? A stack of direct mail?
These mental pictures can help you communicate more clearly and realistically. They help you get outside yourself so you don't create messages aimed at you instead of your real donor.
Try it. It works.