Make sure to limit the points you raise to those you feel are most important. In most cases folks are encouraged to also submit written statements. This provides the opportunity to raise additional concerns. Public hearings are a place for people representing both sides of an issue to address concerns in a public format. It is important to show respect for all sides of the issue, regardless whether or not you personally agree.
Public hearings are a great way to generate media coverage for an issue.
When appropriate bring signs and placards to help convey your message. These are just a few of the ways to get involved in your local community, many others exist. The most important thing is to get involved - period. At Patagonia we agree with the Quaker idea of bearing witness - if you see an injustice, you are obligated to act to correct it. If you aren't part of the solution, you're part of the problem.