They may serve as identification when your point of view is considered. DO be courteous and reasonable. DO feel free to write if you have a question or problem deading with procedures of government departments. Congressional offices can often help you cut through red tape or give you advice that will save you time and wasted effort. DO write to say you approve, not just to complain or oppose.
Public officials hear mostly from constituents who oppose their actions.
A barrage of criticsm gives them a one-sided picture of their constituencies. DO include pertinent editorials from local papers. DO write early in the session before a bill has been introduced if you have ideas about an issue you would like to see incorporated in legislation. If your senator or representative is a member of the committee to which it has been referred, write when the committee begins hearings. If he or she is not a member of the committee handling the bill, write him or her just before the bill comes to the floor for debate and vote.