Be safe. It's not out of the realm of possibility that a few people will try to rile up the crowd and attempt to incite violence. Most town hall meetings will have at least one police officer, so if you see someone doing something dangerous, let law enforcement know.
Leave your signs at home. You won't be allowed to bring them into the venue, and they are distracting and cumbersome for other attendees.
Keep your questions pointed and brief. Don't spend too much time asking rhetorical questions. Make your statement and your question timely and ask specific questions. Practice beforehand if you need to.
Talk to staff. Staffers from the state and DC offices attend town hall meetings. Try to introduce yourself before or after the meeting and have a short conversation. This is a good way to get on their radar and possibly arrange a meeting later.
— Emily Ellsworth
Phone calls do work. According to Emily Ellsworth, best to call "their district (state) office. They have to talk to you there." Staffers keep track of what issue you call about -- so be clear and specific.