Following up is the key to building a relationship with your elected officials, so don't forget to do it! The better you follow up, the more they'll keep you informed when your issue comes up in Congress and turn to you for trusted information and advice.
If Your Congressperson Agrees with You: Don't forget to follow up your meeting with a thank you and a review of your main points. Always take that opportunity to include any new printed information on your issue that you think is relevant (newspaper articles, editorials, letters from organizations in the country you're talking about, letters from your church, petitions, etc). Continue to send materials whenever you see something interesting. Remember, just because they agree with you now doesn't mean that others aren't trying to change their mind. If you keep your position in their mind, they are less likely to change theirs.
If Your Congressperson Does Not Agree with You: Arrange to take other constituents in to meet with them. In follow-up meetings, always reiterate that you are asking your representative to take your opinions, as constituents, into account. Remind them that the issue you are there to talk about is important to you, and, very importantly, to your vote.