It's pretty simple, you need to have a rogue or a night elf.
Go front of any questgiver, hit the stealth/shadowmeld and wait till someone from opposite faction clicks accidentally you instead of questgiver.
This works very often, its very easy to get 1 "kill" in a minute.
Peoples will usually rush to questgivers and start spamming right click while they are approaching the questgivers (atleast if they are in hurry ).
Now, other peoples usually spot you just before they are in front of q-giver (still spamming right-click) and when they spot you, they do attack you instead of talking to q-giverAfter attacking you those guards will have some surprise buttsex with the fellow who ganked you.
You wont get any honor, but the other guy gets repairs and you get laughs.