Anyone have tips on how to master a Korean accent and get rid of an English accent or just accents in general?
Are you that young? If so congratulations for having some ambition. The best advice I can give is to get a language partner. Find a few language exchange websites (you'll need options as you'll want to find someone who is reliable and also has good chemistry with you) and try to talk, as in speak, with them once a week if possible, and message each other far more often than that. Make your mistakes, help him/her with theirs, and you'll see results in a couple months easy.
It is possible, with practice, to learn the language pretty well. https://www.viki.com/videos/59736v-assorted-gems-episode-12 About 10 minutes into this drama episode, and again about 17 minutes in, there is a western actor who does a pretty good job. He actually has a pretty large part throughout the drama. He doesn't quite sound like a native, but has a very natural flow. Just like anything else, it takes lot of practice--both listening and speaking. If you have 50 hours or so to spare, it's a pretty entertaining show, especially to those of us a little more advanced in years.