一、Courtesy 禮貌

　　語言要有禮且謙虛，及時地回信也是禮貌的表現。

　　例如：

　　We have received with many thanks your letter of 20 May, and we take the pleasure of sending you our latest catalog. We wish to draw your attention to a special offer which we have made in it.

　　You will be particularly interested in a special offer on page 5 of the latest catalog enclosed, which you requested in your letter of 20 May.

　　二、Consideration 體諒

　　寫信時要處處從對方的角度去考慮有什么需求，而不是從自身出發，語氣上更尊重對方。

　　例如：

　　“You earn 2 percent discount when you pay cash. We will send you the brochure next month. ”就比 “We allow 2 percent discount for cash payment. We won’t be able to send you the brochure this month.” 要好。

　　三、Completeness 完整

　　一封商業信函應概況了各項必需的事項，如邀請信應說明時間、地點等，確忌寄出含糊不清的信件

　　四、Clarity 清楚

　　意思表達明確，要注意：

　　(一)避免用詞錯誤：

　　例如：As to the steamers sailing from Hong Kong to San Francisco, we have bimonthly direct services.

　　此處bimonthly有歧義：可以是twice a month 或者once two month.故讀信者就迷惑了，可以改寫為：

[1] [2] [3] 下一頁