Do as you would be done by.
己所不欲，勿施於人。
還有壹些也可以看看：）~
Doing is better than saying.
與其掛在嘴上，不如落實在行動上。
Do it now.
機不可失，時不再來。
Do nothing by halves.
凡事不可半途而廢。
Don't claim to know what you don't know.
不要不懂裝懂。
Don't have too many irons in the fire.
不要攬事過多。
Don't make a mountain out of a molehill.
不要小題大做。