Rule #1: Never screw over your partner.
Rule #2: Always wear gloves at a crime scene
Rule #3: Never be unreachable.
Rule #4: The best way to keep a secret? Keep it to yourself. Second best? Tell one other person if you must. There is no third best.
Rule #5: You don't waste good.
Rule #6: Never apologize, its a sign of weakness.
Rule #7: Always be specific when you lie.
Rule #8: Never take anything for granted.
Rule #9: Never go anywhere without a knife.
Rule #10: Never get personally involved on a case.
Rule #11: When the job is done, walk away.
Rule #12: Never date a coworker.
Rule #13: Never, ever involve a lawyer.
Rule #15: Always work as a team.
Rule #16: If someone thinks they have the upper-hand…break it!
Rule #18: It's better to seek forgiveness than ask permission
Rule #22: Never, ever bother Gibbs in interrogation
Rule #23: Never mess with a Marine's coffee if you want to live
Rule #27: Two ways to follow: First way, they never notice you. Second way, they only notice you.
Rule #35: Always watch the watchers.
Rule #38: Your case, your lead.
Rule #39: There is no such thing as coincidence.
Rule #40: If it seems someone is out to get you, they are.
Rule #44: First things first. Hide the women and children.
Rule #45: Clean up your own mess.
Rule #51: Sometimes — You're Wrong!