A few useful ones spring to mind:
息息相關 - to be very closely related
不寒而栗 - to shiver but not from the cold (from fright)
寥寥無幾 - for there to be almost none
迫在眉睫 - to be very urgent
因人而異 - to differ depending on the person
飛黃騰達/平步青雲 - to make great progress in your career
汗流浹背 - to be really sweaty
五花八門 - lots of different types of a thing
司空見慣 - for something to be commonplace
節哀順變 - what you say to someone when someone passes away
坐井觀天 - to have a narrow outlook on life
置之不理 - to ignore something
一模一樣 - to be exactly the same
鴉雀無聲 - to be silent
奄奄一息/彌留之際 - to be on the verge of death
一無所有 - to have nothing
一本正經 - to be very serious
一如既往 - the same as always
引人注目 - to attract attention
迫不及待 - to be unable to wait
Laurence