Of COURSE letters and emails make a difference. I sent one last month, as did DH, to an alderman in an adjacent ward. It was input she asked for, about a development within my neighborhood.
I uased to send only snail mail to aldermen, but they indicate email is just as effective. You need to craft your own message, that is key. DH and I had different negative reactions to this development and our messages were different, but both gave concrete reasons why the development shouldnt fly.
For those of you stuck at the National level of politics, I would not use any pre-printed postcard from any organization, women's march or whatever.
Your own thoughts, expressed succinctly and legibly via your own communication tool is what is effective because it shows you are self confident enough to reach out and communicate. You are, for sure! a voter in the eyes of your representative. If you send generic postcards, that is the same as online petitioning and people who do that may not even get up off the couch to vote. Snail mail form messages are like cutting and pasting an email message from someoene else. . Be an individual not a drone, the politicians want to hear from individuals.
I also dont understand what is so hard about making a freeking phone call. Those congressional staffers work FOR YOU. They are there to take phone calls FROM YOU.