When you write Congress, you speak for hundreds of other people.

That’s the lesson from Grover Norquist, a longtime anti-tax advocate and founder of the group Americans for Tax Reform.

In a recent interview with Congress.org, he said that businesses have a rule of thumb that each letter they receive represents another 200 people who had a similar concern.

“Two hundred people thought about it, were mad, went home mad, said I’m going to write a letter, and then forgot to write the letter because they got busy,” he said.

Still, there’s more to it than just sending a letter, he said.

Here are a few other tips from Norquist:

* Tell — don’t show — your anger. Writing in all capital letters or using foul language just makes you sound unhinged. “You can say how unhappy you are without swearing or calling anybody stupid,” he said. “You can say, ‘I’m very angry.’ You don’t have to sound angry. You can just say it. ‘I’m very angry. This really irritates me. This is very bad.’”

* Don’t be unreasonable. If the tone of your letter makes you sound as though you won’t be happy no matter what politicians do, they’ll ignore you. “They think, ‘How can we please this person? They’re crazy,” Norquist said. “I have a very nice crazy file in my office, but I tend not to write back to those people.”

* Tell them if it’s your first letter. Norquist said it’s very effective to let Members know this is the first time you’ve written or that you haven’t written in a long time. It helps them understand how strongly you feel about the subject of your letter, he said. He compared it to the joke about the boy who ends years of silence to complain about the broccoli at dinner. “Until now, everything’s been fine,” he said

* Narrow your focus. Norquist said too many advocacy groups focus on a laundry list of issues. It’s more effective to focus your energy on a single issue, he argued, pointing to advocates for home-schooling who have done well in fights against teacher’s unions. “That’s like marijuana growers went up against (pharmaceutical companies) and beat them,” he said.

* Act locally. If you want to meet your Member of Congress in person, track them down when they’re in town — not when they’re in Washington. “I was a quiet critic of the idea of bringing people to D.C. for a rally,” he said. “Why would you do that? If you have 1,000 people in North Dakota, have them talk to their guy in North Dakota.”

Ryan Teague Beckwith is deputy editor of Congress.org.

Lee ADDS: When writing Obama, the useage of Dear A..HOLE is petrmissable!