I send emails mostly, It is much quicker and gives the opportunity for immediate response. Like when Phil Donahue was looking for ideas a for his "comeback" show.I emailed him with the idea or rebroadcasting a previous show that projected cannabis in a very favorable way. Received a reply in maybe two minutes...and that show was rebroadcast with open discussion and links to "hardball" discussion.
In other words I write to people now who get me results or at least replies. Mayor of Pittsburgh...Governo r ..etc.
I admit I used to do what you do. Actually physically writing to local state and federal authorities, with little response/reply.
My biggest platform for activism actually now is newsvine discussion.
It gives the opportunity to respond directly to the author of a particular article, or reply to anothers response...much like here, but with much less censorship. The membership is nearly infinite as are the topics. The replies are swift and merciless for the uninformed on a number of issues. Marijuana legalization be a reoccuring one of my favorites.
I appear as "dogmeat" (seemed appropriate @ the time).