MIT一老师对于推荐信内容的一些意见

Be specific. Don't just praise the person with generalities (such as "quick learner"), but give specific examples of things the person did to give you that impression. Rankings in class are another example of a helpful specific.

Differentiate. Say how this person is unlike other people: his or her specific strengths.

Compare. When writing to someone who shares context with you, name names. ("The best student I've graduated since little Al Turing.")

Be plausible. Don't make the person out to be perfect. Often shortcomings are just ignored, but it can also be reasonable to note some, particularly if the person has started to overcome them.

Say how well you know the person, and for how long. This should come at the beginning of the letter.

State your own qualifications. How many other people of the caliber the recommender sees have you yourself seen. (For example, the best student in years at some places might not be appropriate for MIT; but someone who got a PhD from MIT or was there on sabbatical carries more weight in a recommendation to MIT, because that person's scale has been calibrated.)

Don't be too brief. One paragraph, or two short paragraphs, is the kiss of death. (If you don't know the student well, and don't have much to say, add a short paragraph explaining what the course is and why it's good that the student excelled in it. This won't fool most people, but will soften the blow of a short letter.) However, don't ramble: make it succinct and to the point.

原文：http://people.csail.mit.edu/mernst/advice/request-recommendation.html