When expressing a generally accepted truth/maxim or giving 'soft' advice, the following three part structure can be used:
젊을 때 열심히 공부해야 좋은 대학교에 가지.
You should study hard when you are young so you can go to a good university.
친구가 힘들 때 도와 주어야 진정한 친구지.
A friend in need is a friend indeed.
(lit: When a friend is in difficulty and you help, you're a genuine friend)
고기를 양념할 때 굽기 전에 최소한 1을 숙성시켜야 더 맛있지.
When you season meat, it should be marinaded for at least a day before roasting it, then it will taste even better.
스타디움에 있는 콘서트에 갈 때 일찍 도착해야 보는 무대의 전망이 좋지.
When you go to a stadium concert, you should arrive early and then you'll get a good view of the stage.
문제가 있을 때 친구랑 이야기를 해야 기분이 더 좋지.
If you have a problem you should talk to a friend and then you'll feel better.
햇빛이 강할때 몸에 선크림을 발라야 피부가 햇볕에 안 타지.
When there's strong sunshine you should put sunscreen on and then your skin won't burn.
다른 도시로 이사할 때 새로운 친구들을 만나려고 해야 외로움을 느끼지 않지.
When you move to a new city you should try and make new friends so that you won't feel lonely.