You will need to bring your personal hygiene products like your deodorant and toothpaste, because it might be hard to find them in Korea. You might want to pack your favorite brand for a month because Korean brands simply aren’t the same. Trust me! If you like the taste of home bring some of your favorite food or ingredients to make home cooking as they have a cooking area. Even though the food in Korea is delicious some might have a hard time with it so be sure to have some back up snacks. Also when you are missing home the snack you brought might just help with easing that sorrow. Korean food can be spicy so if you cannot eat spicy make sure to have backup.
Make sure to have an outlet converter, last year I went I forgot to bring one and had to spend my summer abroad sharing a converter with my roommate (it sucked). Also I recommend bringing a power strip to plug into a converter, giving you more outlets and won’t have to constantly plugging and unplugging things. If you have a labtop bring it as it may be useful to use it for school work but also keep in contact with family and friend with skype etc. The school provides you with a pillow and thin blanket, but if you leave the AC on and night and go to bed, it might be wise to bring an extra fleece blanket to keep you snuggle at night.
If you are people that enjoy nightlife, bring some clubbing clothes. Korea has a lot of night activities so I highly recommend it. Also the last day of summer abroad at KAU they have a graduation ceremony (small one) some might prefer to dress up nicely for the pictures (suit and tie).