"You listen well, brother."

"I'm listening."

Loki & Thor in The Avengers

-

1. Do not use contractions often

2. Use old English whenever thou can.

3. Pretend to be surprised (or amused) by silly Midgardian Customs.

4. Pretend not to know an English term every now any then (even though English appears to be Asgard's main language)

5. Call Earth 'Midgard'.

THOR

- Call Tony 'Metal Man'

- Laugh at petty mortal things

- Try to solve problems the Asgardian way

- Call Loki 'brother' even though you know he hates it.

- When around Bruce, never cease to repeat the phrase "sun's getting real low" in an annoying fashion that is more likely to make him Hulk out than it is to make him calm down

LOKI

- Call anyone who annoys you 'mortal'

- For good measure, you could always tell them to kneel

- You are above those mewling quims. Embrace it.

- World domination requires effort. But you'll get there

- If Thor calls you brother correct him angrily within seconds

- Avoid the Hulk. For real, that guy's not one to mess with.

- stab stuff

HELA

- Speak slowly with a drawl that makes you sound super-villain-ish. Better let people know what they're getting into

- Subjugate. everyone is beneath the Asgardians, and the Asgardians are beneath you.

- Exasperation is key

LADY SIF

- Avoid contact where possible

- Be violent and awesome

- If you're unsure what to do, copy Thor or Fandral

VOLSTAGG

- Eat

ODIN

- Just don't come to Earth to begin with

- Obey standard rules and act king-ly

- If something goes wrong, you can always fallback to Plan Odinsleep

FRIGGA

- Try to convince the world Loki's not as evil as he looks, even though nobody will listen to you.

- Be queenly and wise

- But don't forget to badass whenever necessary

HEIMDALL

- Be mysterious and say as little as possible

- But secretly support Thor

- Do what is right even if the King says it's wrong 

- especially if the King's name has four letters and an o and an i

- stare into the distance when bored to pretend you're seeing something other than the Asgardian sunset

- Also if Loki tries to freeze you just dodge you idiot

- Don't loose your cool and always be calm

- Even when frozen by the Casket of Ancient Winters

[ if I'm forgetting anything important, let me know and I'll add it in ;-) ]