Don't go to a wedding without wearing chainmail.
Actually don't go to a wedding. If your attacker plans on using poison, chainmail is useless.
Dont confront someone about them having an incestuous relationship with a sibling.
Don't be an asshole.
Keep your dogs well fed.
Know when to keep your mouth shut. A lot would agree Joffrey as King is a disaster. None of them said anything and they're still alive.
Don't insult a mans wife.
Keep church and the state separate.
Don't demand something you don't deserve.
Dont get too cocky. You'll just end up with a killer headache.
Always do what is right, even if it gets you killed. If you're a god among men, you'll come back.