It's that time of year again, when lots of people are getting ready to start new jobs at Korean unis, perhaps for the first time ever if they're making the transition from a hagwon or public school. Exciting times! I remember how nervous I was about the whole thing. This post, back from 2011 was one of my most popular ones ever and might be helpful in this situation: Ten Tips for Newbies to the Korean University Teaching Experience.
The only thing I wouldn't necessarily agree with anymore is #7 about class size. Sure, smaller is better but it wouldn't be a big factor for me in taking a job, or not. With a bit of experience, teaching a class of 40 or 50 is really not a big problem.