再见。
See you. / Goodbye.

Explain:
再 again
见 see
Notes:
“再见。” means “See you. / Goodbye.” This is one of the most common everyday Chinese phrases. You may say it to anyone when he is leaving, or when you are leaving.

走好。
Goodbye.
Explain:
走 go/walk
好 good/well
Notes:
“好” means “Goodbye.” This is a colloquial polite expression, which is often used as a host's reply when his guest, especially the elderly, the disabled, a weak or a pregnant lady says goodbye to him. It just shows his concern for his guest.

慢走。
Goodbye.
Explain:
慢 slow/slowly
走 go/ walk
Notes:
“慢走。” means “Goodbye.” This is a common polite expression, used as a reply when the guests say goodbye to their host. When the Chinese host say this to his foreign guests, they often feel strange. They wonder why the host asks them to walk slowly. But this is the Chinese custom.

晚安！
Good night.
Explain:
晚 night
安 good
Notes:
“晚安！” means "Good night." and is used among close acquaintances or the family members when they say goodbye to each other before going to sleep at night. Please notice that an anchorman may say "Good night." to his audience or listeners at night before his program ends.

明天见。
See you tomorrow.
Explain:
明天 tomorrow
见 see/meet
Notes:
“明天见。” means "See you tomorrow." This is a common phrase which can be used on many occasions. You may say this to anybody when you know you will see him next day.

多保重。
Take care of yourself.
Explain:
多 many/much
保重 =take care of oneself
Notes:
“保重。” means “Take care of yourself. ” This is a formal polite expression used to say goodbye to someone you concern, especially family members, friends, the elderly, the sick, or a pregnant lady etc.

我走了。
I am leaving.
Explain:
我 I
走 go
了 (modal marker)
Notes:
“我走了。” means “I am leaving. This is frequently used among close acquaintances in the Chinese everyday life, when you just want to say a simple and direct goodbye to your friends, your colleagues or your classmates etc.

一会儿见。
See you soon.
Explain:
一会儿 soon/a little while
见 see
Notes:
means “See you soon.” It is a very common phrase. You may use this phrase to say goodbye when you know you will see someone very soon.

路上小心。
Take care on your way.
Explain:
路上 on the way
小心 be careful/take care
Notes:
“路上小心。” means “Take care on your way.” You can use this phrase to say goodbye to your family members, colleagues or friends etc., especially when they are driving or walking home alone in the evening, at night, in icy conditions or in any bad weather.

保持联系。
Keep in touch.
Explain:
保持 keep
联系 touch/contact
Notes:
“保持联系。’’ means “Keep in touch.” This is an informal and friendly expression. You may use this phrase to say goodbye when you know your close friends and you will not often see each other later.