No one can be expected to address every question or matter of concern regarding an issue, however, so don't hesitate to admit your lack of knowledge on a particular point. Be willing to pursue the answer and report back. It is preferable to anticipate the opposition and answer their arguments positively before those arguments surface publicly. DO Address your Senator or Representative properly. Identify yourself immediately at each contact.
Public officials meet too many people to remember everyone.
Know the status of the legislation. Refer to a bill by number whenever possible. Use your own words. Be brief and explicit, courteous and reasonable. Establish your own credentials or expertise on the subject of legislation under consideration.