There is an excellent write up of how this works and why it works from a former congressional aide: https://qz.com/836737/fomer-congressional-staffer-twitter-ti...
Take action!
Write your senators numbers on a note by your desk, put them in your phone as contacts. Add your house representatives as well. When you hear about an important issue, make a quick call. Ask them to represent you on upcoming issues. Thank them for their position on issues you support, let them know you are disappointed in them for things you oppose.