第一段概括写出写信的大致内容：I am writing here to provide some advice to improve......\You have asked me for my advice concerning/with regard to......
第二段详述具体的建议，可分条阐述：To begin with,......Besides,......Moreover,......
第三段总结段：I hope you will find these suggestions useful and I would be ready to discuss this matter with you to further details. I am looking forward to your reply and wish you a good work.
I’m sorry to learn/hear that…
It is really a pity that you failed in…
Please don’t feel too much distressed(痛苦，紧张) for this frustration.
All of us are waiting for your rapid recovery/return to health(恢复健康).
Please let me know of any assistance I can render you.
Dear Mr. John,
I am exceedingly(非常) sorry to hear that your father passed away.The painful news reached us this morning, and we were so shocked that we could not at first realize the fact.
This sad news has put me in full sympathy with(深切同情) you. Your father was an honorable man and tender parent. Everybody who has known him must feel a great loss caused by his death. I quite understand how you feel now, but you are in duty bound to(有义务) look to your own heath and to take care of your family affairs. These would be impossible if you indulge your feeling in grief.
Please accept the deep and true sympathy which is all I can offer.
第一段首先致谢：I am grateful to be employed as 职位+时间。Thank you for your kind attention and I would appreciate the opportunity of having worked here.
第二段表明自己要辞职，列出原因，比如离家远想换到更近的位置;工作不适合自己等等。现在给大家一个例子：However, I regret having to resign from my position. The reason for changing my working plan is that I have expected the job to be interesting and challenging, which turns out to be the opposite. As a young man full of enthusiasm, I therefore decide to quit this job for something else.
第三段简单表明希望得到允许、歉意及祝福：I sincerely hope that you approve of my resignation. I am sorry for any inconvenience caused. Wish you and your company great success in the future.