What advice would you give to a foreigner coming to Korea for the first time?

If you(foreigners) come to Korea, i want to recommend our traditional food like kimchi, bibimbap etc.

There are so many kimchi in other countries, but the original is Korea.

And if you want to know about Korea, you had better go to the GyeongBokgung, Gyeong ju etc.

You can go to the unconventional place because It is commonplace like GyeongBokgung, Gyeong ju, but it's best place to know about Korea history.
Furthermore, if you want to know about Korea tourist attraction, you can go to the place like Insa-dong, Jeongdongjin where almost people knows.

And it will be helpful to you if you can speak Korean even though your Korean ability is not fluent.
So welcome to Korea!