As posted, keep it to one page if at all possible. Write it like the person is standing there looking you in the eye; don't scream, don't threaten. Keep the letter simple and directed at one issue. It's gonna be read by an aide and at the end of the day, the pol will get a report of xxx number of folks are for, and xxx number of folks are against. If you state a single pertinent item about the issue, it may be gleaned and given to the pol but quoting a lot of stats isn't gonna change much or anything.
Honorable xxxx
I would like to speak strongly against the pending legislation about gun registration. (the aide may well read only that first line) History shows us that gun registration is most often the first step to the disarming of a country's citizens. So a vote against gun registration is really a vote in support of our country's constitution and the 2nd amendment. As an elected official, I am sure that is one of your first concerns
Thank you for you time,
Sincerely,
Beemanbeme
Head of the Holler
Wild and Wonderful West Virginia