There is a mistake in each sentence. Find and correct it

There is a mistake in each sentence. Find and correct it.
1.      Vietnamese people prepares for Tet several weeks beforehand.
2.      Mount Everest is the most highest mountain in the world.
3.      Da Nang is very interested. I really like it.
4.      They‟ll go abroad next year if they had enough money.
5.      You look tired. You should work so hard.
6.      If you read more, your vocabulary will get gooder every day.