E-mail almost doesn't count. What congressional staffers have told people actually works is snail mail. Hand-written, longhand, manuscript letters on heavy bond paper are the best way to go.
Staffers often separate issue letters out by issue and weigh them when the traffic is hot and heavy on an issue like this -- so don't use onionskin or airmail stationery.
The Beltway reasoning is, a manuscript letter someone cared enough to sit down and write, counts for ten other people who felt strongly but didn't have time to write. That's why longhand letters on personal stationery count more -- far more than e-mail, which anyone can dash off in response to an on-air call to arms from Rush or Beck or Mike Savage.
You only need one address to get your letter to your congresscritter:
Congresscritter X (party, state -- to relieve ambiguity)
THE CONGRESS
Washington, DC
You don't need an office number, a street address, a congressional building name, or a ZIP code. The Post Office has never lost the U.S. Congress in over 200 years, and they won't lose it now.
“The Post Office has never lost the U.S. Congress in over 200 years..”
Maybe that explains why they think they’re Santa Claus.