( Originally Published 1912 )
1. Do not argue about everything.
2. Never belittle your opponent.
3. Control your temper.
4. Be impartial in your search for truth.
5. Seek to make a favorable impression.
6. Cultivate calmness and candor.
7. Do not resent opposition.
8. Avoid egotism.
9. Keep your eyes on all your company.
10. If you agree in part with an opponent, say so.
11. Do not be obstinate.
12. Many trifles may go unchallenged.
13. Be concise.
14. Hear others with patience, as you yourself would be heard.
15. Avoid high key.
16. Don't quibble.
17. Have a main point to prove.
18. Never fear to put the truth on trial.
19. Avoid generalization.
20. Look your hearer in the eye.
21. Do not argue with your hands.
22. Speak distinctly.
23. Avoid personalities.
24. Do not emphasize the obvious.
25. Define your terms.
26. Keep some ammunition in reserve.
27. Make a strong ending.