First off, the two hand rule. Generally when I am interacting with someone older or considered my superior (such as a boss or client), it is expected that I will use two hands when shaking their hand, pouring them a drink, accepting a drink, as well as many other interactions.
Here is the proper way to accept a drink (note that the recipient will hold the glass with 2 hands):
We tend to not like to pour our own drinks, something about bad luck. This is why usually there is always someone pouring each other drinks.
It is generally considered rude to drink by yourself if there is company around. This is a social activity. We will wait to "cheers" or "gombae" in Korean before taking the drink. Now as I am raising my glass, I am still using 2 hands.
Now we finally get to drink. Hold that thought! Technically, still assuming I am either the younger one or not in the position of power, when I take my drink, I am supposed to turn my head away from the people I am drinking with. This is a sign of respect.
Now most people will at least accept the first drink and assuming it's a shot, will down the whole thing. Again this is a show of respect. After the initial shot, it is more than okay to just sip on your drink or even let it sit. We Koreans prefer to not see our drinking companions with empty glasses though, it makes us feel guilty, as if we are drinking by ourselves.
You have just graduated from Korean drinking 101. Cheers!
Here is a fun video I found on Youtube also demonstrating the Korean drinking etiquette:
https://www.youtube.com/watch?v=plywvyKnU4Y&noredirect=1
Also be sure to check out my blog on the Korean Dating Scene:
http://koreatowndating.blogspot.com/
