I've been told by U.S. Senators and Congressmans, as well as Indiana Senators and Representatives, that some of them will give weight to a simple telephone call. Others want telephone calls and emails because they become "bullet points" for when the aide is presenting it to the official. Others give the most weight to snail mail contacts because the constituent took the time to write and mail the letter, whereas it is relatively easy to dial a telephone or fire off an email as compared to the process of writing a letter.
I have had to contact Bayh in the past, and he doesn't like/return telephone calls. He was so-so on returning emails, but he did answer my snail mail letters.
I've called, written letters and emailed. Only thing I haven't done is to go to their office. Bayh sends a letter if you ask for an answer. Lugar sends a letter to let you know he disagrees with your stance and yet wants his pat on the back and cookie for looking out for you. All done by their office flunkies (aka aides). A call to their office usually yields the call answerer saying they'll pass along your opinion to your Rep. Emails have merely gotten me on their mailing lists... emails about what a good job they are doing for us, the lowly caste. I personally think they should be required by law, to hold town meetings a few times a year to directly answer to constituents.
But anyway... good luck getting the elite class to listen to you.
I sent Pat Miller an email questioning something she was quoted in the paper as saying, and SHE CALLED ME a couple of days later to hear my concern and explain her stance. I still didn't agree with her 100%, but my opinion of her rose considerably.
Or meet with them in Washington. Schedule an office meeting with them, if they walk home or take the subway, hook up with them that way.
My favorite, get lucky and have a seat on an airplane next to them and they are stuck with you for the flight.
Call and ask them to call you back.
All of the above have worked for me. Also if you arrive before security sets up at the meeting, they might not know you are there. That is a funny story for another time.