http://www.topikguide.com/previous-papers/ Download the old test papers of TOPIK (Test of Proficiency in Korean), and take a look. There you can find many vocabulary that can come really handy since these questions are very considerately chosen ones.

My thoughts on learning vocabulary in general: https://www.italki.com/discussion/91279 The best words to learn are the ones you will personally see, hear, and use the most often^^ There's talktomeinkorean.com, howtostudykorean.com, quizlet.com, memrise.com, ankisrs.net, and many others. Too many to remember. Here's a dictionary: endic.naver.com Remember, anything can be a source of vocabulary: Try writing or saying something. Think of a word you don't know? Look it up, use it, learn it. Try reading or listening to something. See/hear a word you don't know? Look it up, use it, learn it. Of course, try to pick materials at an appropriate level/personally relevant and prioritize learning words (conversational vocabulary over vocabulary to read newspapers).

I recommand http://www.sejonghakdang.org/sjcu/home/main.do I think, you could see many useful contents .

In addition to talktomeinkorean.com, I'd recommend the site www.howtostudykorean.com/ which has a vocabulary list with each lesson.

If your main focus is vocabulary, I would recommend trying Memrise. I know there are several popular Korean courses there and the site is free (unless you want to use the optional premium features). http://www.memrise.com/courses/english/korean/ The Reddit Korean sub is also a great place to find information and help, or talk with other learners: https://www.reddit.com/r/korean