独占鳌头；首屈一指；出人头地
bear (or carry off) the palm
He carried off the palm by sheer perseverance.
　
兴风作浪；惹是生非
make waves
We've finally settled our differences, so please don't make waves.
　
兴高采烈；喜不自胜
bright-eyed and bushy-tailed; full of the joys of spring
Here is my new kindergarten class, all bright-eyed and bushy-tailed.
He bounced into the office, full of the joys of spring.
　
随心所欲；一意孤行；自行其是 (想怎样就怎样)
be a law unto oneself; have it one's (own) way
You can't tell Mary how to punctuate; she's a law unto herself.
Oh, have it your own way — I'm tired of arguing.
　
随波逐流；随遇而安
swim/drift/go with the tide/current/stream
Bill doesn't have a mind of his own; he just swims with the tide.

附注：这成语的相反词，即「不随波逐流」，叫做 "swim/go against the tide/current/stream"。

随风转舵；随机应变
trim one's sails (before/to the wind)
His advisers told him to trim his sails before he alienated voters and bungled the election completely.

昙花一现；虎头蛇尾
a flash in the pan
His second novel proved to be a flash in the pan.
We had high hopes for the new director, but she was a flash in the pan.

战战兢兢；提心吊胆；胆战心惊
in fear and trembling
I went to him in fear and trembling to seek his acceptance of my apology for my rude remarks.

擅离职守；不告而别
take French leave
Is Randy really ill again, or is he just taking French leave?

谋事在人，成事在天
Man proposes, God disposes
My father usually says that man proposes, God disposes.