"Please," "Thank You," and "I'd be willing to visit or help."
Short but informative:
1. Executive summary - Please support, oppose, or help us pass or defeat;
2. Brief details that support your summary;
3. Offer for more information or discussion if they wish;
4. Appreciation for what they do and will do in advance.
You would be amazed at the total lack of respect our representatives deal with day in and day out. This comes not only from us and lobbyists, but from their colleges as well. They endure not only abuse for their views, but even vulgar language on a regular basis. I was at a hearing and listened to teachers direct language at the committee that they complained about in their classroom.
I make a point to include my thankfulness for their service and my appreciation for the tough choices they must make daily even when I don't agree with their viewpoint. This has created a relationship that keeps me as one they don't shy away from, because even if I think they are acting like a "jackass" they know I will say it in a civil manor.