Use a single spokesperson, whenever possible. Bring in technical expertise when needed, but don't cover the same ground repeatedly. Be there all the time. Effective advocacy is not part-time work. If you offer to be a resource, be available.
Return calls promptly.
Never hand officials a pile of reading matter. Condense issues into short fact sheets and offer backup as needed. Cultivate personal relationships, where possible. Be a gracious winner and a good loser. Never hold a grudge if issues go against you.