Don't gild the lily.
不要给百合花镀金/画蛇添足
The empty vessels make the greatest sound .(William Shakespeare ,British dramatist )
满瓶不响,半瓶咣当
Do not ,for one repulse ,give up the purpose that you resolved to effect .(William Shakespeare ,British dramatist)
不要只因一次失败,就放弃你原来决心想达到的目的