如果你要请别人帮忙，并且可能不会有多少报酬，还要占用对方的时间或是花费金钱，这样的求助成功的可能性不会很大，除非你能说服对方这件事能给他带来潜在的益处。

商业上求助的时候，通常都要写一封说服信。下面是求助说服信的写作原则：

1. Learn all you can about your reader and tailor your request to the reader's interest or concerns.
2. Find rational, emotional, or moral appeals that might attract your reader's attention.
3. State specific benefits which your reader might value.
4. Offer enough information upon which your reader makes his decision.
5. Close by making your request confidently.

下面是一封邀请演讲人的信，大家来看看这封信是如何写的：

Dear Dr. Longh

Your recent article "Major Principles of Financial Management" in the Journal of Financial Economics has drawn many favorable comments from our managers and bankers.

Although many middle level managers have experience in the financial field, some of us lack theoretical background. We, the Financial Manager Club, feel a strong need for more practical guidelines in financial management. Your expert opinion would be a big help to us.

About 150 financial managers will be attending our annual managers' meeting. They would be glad to meet you and share their problems and concerns with you.

Being a speaker at this annual meeting, you will be able to present your perfect specialized experience which is supposed to be reported on China Daily, one of the popular newspapers in our country. In the meantime you will also have an opportunity of meeting some of the executives from major banks and corporations.

Your wife is also invited to be our guest at the banquet, which is to be held at the Golden Dragon Hotel on Friday, May 3. The schedule for the program is:

Cocktail 17: 10 - 17: 30
Presentation 17: 30 - 18: 10
Questions & Answers 18: 10 - 18: 40
Dinner 18: 40 - 20: 00
Entertainment 20: 00 - 21: 00

The program needs to be announced to our club members on April 30. Will you kindly let us know by April 29 whether your busy schedule in Beijing will enable you to accept our invitation?

We are looking forward to your favorable reply.

Sincerely yours

（例文来源：《国际商务写作教程》，对外经济贸易大学出版社 英语点津 Annabel 编辑）