當獲悉某人晉升或是在事業上取得巨大成就時，應該打個電話或是寫封便簽祝賀。這種友好往來對建立和鞏固友好的商業合作關系大有益處。

Here are some principles that congratulatory letters follow:

1. The purpose of writing the letter is to make your reader feel certain that he or she deserves the special message of recognition and praise.
2. The note should be brief, dealing with the primary topic only. These messages are most effective when they conduct no business.
3. The whole message should carry a tone of being positive and conversational.
4. Be sure to send the letter within a few days of the event. Any delay in delivery of the message would make your effort worse than no effort at all.

下一次，我們將給大家分析一些祝賀信的實例，別錯過哦。

（來源：《國際商務寫作教程》，對外經濟貿易大學出版社 英語點津 Annabel 編輯）