“好酒不怕巷子深”英文可以说"Good wine needs no bush." 出自莎士比亚戏剧"As You Like It".
Good wine needs no bush.
William Shakespeare (1564-1616)
As You Like It, Epilogue.
"It was customary to hang out ivy, boughs of trees, flowers, etc., at public houses to notify to travellers that “good cheer” might be had within."
-Dictionary of Phrase and Fable. 1898
旧时，酒馆门口挂些常青藤、树枝或是鲜花。 但是如果地方好，酒香，门口不用挂常青藤，别人也知道这个地方。也就是"Good wine needs no bush."
不做广告，那就要靠好的口碑了：Word of mouth (=information you get by someone telling you) is one of the best ways of getting business.
靠口碑来宣传:word-of-mouth marketing
客户满意服务的话，可以请客户写一封推荐信: a letter of reference
国外还是比较注重推荐信，无论是申请学校还是工作，很多时候都要推荐信。
中国人还有一句老话，“好事不出门，坏事传千里。”
英文也有类似的话：
Bad news spreads/travels fast!：
People are quick to discuss the misfortunes of others.
The New Dictionary of Cultural Literacy, Third Edition. 2002.
其实西方人和中国人一样的爱面子，要不英语中怎么会有"Don't wash your dirty linen in public", 和"Everyone has a skeleton in his closet."这样的谚语？
Don't wash your dirty linen in public. - 家丑不可外扬。
Everyone has a skeleton in his closet. - 人人皆有不可告人之事。
好像有点跑题了。:-) Am I getting side-tracked?
如果一个人很出名，那么这个人就是 a person who needs no introduction
家喻户晓的东西或是人物是：a household name
比如说，2005年的超级女声冠军李宇春就是个很好的例子： Li Yuchun is now a household name in China.