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, dealing¹ 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 conversational².
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.

讲过了祝贺信写作应遵循的一些准则，下面我们通过一封信件来看看具体的写作方法。

Dear Mr. Haskel
Congratulations on your recent promotion³ to head the Marketing⁴ Department of California Metals.
My fellow managers and I are delighted that your work in the marketing field has been recognized this way and we join in sending you our very best wishes for the future.
Through the five years of working together with you, many of us well aware of how much you've contributed to the association between our two corporations. We are all looking forward to your trip to China next month when we will celebrate your advancement⁵ in a more formal way.
Again, congratulations to you, Mr. Haskel - good luck and good wishes on your new position as Director of Marketing Department.
Cordially yours
(Signature)
Lin Daming
Marketing Director
Beijing New Metals

在这封祝贺信中，写信人一开头就开门见山的祝贺收信者晋升，然后又详细写明自己对对方工作的欣赏、成就的肯定。在信件结尾的部分，写信人用口语化的语气再次祝贺对方的晋升，并以此结束信件。祝贺信写起来很简单，对吧？