This website makes it very easy to connect with your representatives and tell them what you think. It’s set up for calling, but I often use it for ideas and then send them by email or postcard. It has prompts in case you don’t know what you want to talk about.
Text Resist to 50409 on your phone. This is useful way to reach out to your members of congress if you have a smart phone. You need an idea of what you want to say before texting.