Don't seek support of science as an entitlement. Don't convey negative attitudes about politics and politicians. Perform good intelligence gathering in advance. Always use a systematic checklist. Do your homework on the issue or problem.
Timing is vital.
Understand Congressional limitations. Make it easy for those in Congress to help you. Remember that Members and staff are mostly generalists. Don't patronize either Members or staff. Don't underestimate the role of staff in Congress.