Essay，属于文书材料的一种，一般见于本科和MBA的申请，研究生申请多以个人陈述为主。相比个人陈述，Essay的主题更为宽泛，文体、结构、用词、文笔等都有更为广阔的发挥空间。
作用
在申请中，Essay的作用相对较大。按羚羊网的2013年的一项统计，Essay在本科申请中的作用排在第五位，仅次于GPA、中学课程难度、标准化考试成绩和班级排名，属于非学术性材料中最受重视的材料。而在MBA申请之中，不少人甚至认为Essay的重要性占到全部申请材料的40%以上。
写作与润色
写作ESSA/PS时，建议要多阅读范文，但又不要被范文所囿，束缚了自己的思想。建议先确定文章主题，Common Application和学校官网一般都会给出一些主题，但也完全可以自己想。再用中文将Essay/PS写出，然后再翻译成英文，多做润色和修改，最后定稿。
润色原则
文书修改与润色许多人爱找英语好的同学，甚至自己的老外亲戚帮忙，又或者找中介的团队帮忙，但请记住文书核心是：Motivation & Qualification，这类润色与修改切忌过头！
文书修改的请遵循以下两个原则：
- 原则一：不要过分追求文字达到母语（Native Speaker）的水平
- 原则二：吸收正确的修改意见
文字润色
原则：不要过分追求文字达到母语（Native Speaker）的水平。
ESSAY/PS是用来展现自己某方面的优秀特质或经历的，本来就该用中文，只是对方没法看懂，没办法，只有翻译成英文了。让英语好的朋友或同学，甚至让国外的朋友帮忙修改文书是不错，但不要迷恋，整得至于每个表达都要做到地道才罢休。记住，ESSAY不是用来秀英语作文的——这个该在TOEFL或SAT写作里秀，如果你TOEFL作文考得一塌糊涂，你就那么肯定招生官不会生疑吗？
著名的升学指导专家 Ana Ivy （曾经在法学院做过admissionofficer），针对这一问题，她的看法是：
“It's your application, so ultimately it's your call. But I can tell you, from my own experience as an admissions officer, that any essays that sound 'too perfect' from an ESL applicant willraise red flags, and then the admissions officer will come to doubt the authenticity of the rest of your material too.
You run the risk that they'll suspect your essays were written by someone else, or that the essays have been 'scrubbed' to the point where not even the content is your own. And that's a huge mark against you, so you are much better of submitting the writing in your own voice.
Nobody will hold against you that your English doesn't sound totally native. Authenticity is a big part of what makes application essays successful, so you've actually made your essays worse by having them worked over by native speakers to get the English 'perfect.'”
简单翻译下这段文字的要点：
（1）作为一个非母语申请者，文书写得那么地道，老外不大信；
（2）文书写得地道，其它材料却明显跟不上——TOEFL写作分数奇低这种不知道算不算，她没说——摆明就是想让招生官怀疑你找人代写，进而怀疑你ESSAY的内容是不是也在作假！
（3）真实性压倒一切——不地道不要紧，没一个老外吃饱撑得要求一个非母语的申请者写出完全地道的ESSAY，找老外帮你修改只会适得其反！
吸收正确意见
注意是“正确”的修改意见。如何吸收别人的建议是很关键的，如果没有原则，来者不拒，那么周围人过多的意见只会干扰你，让你迷失方向。特别是那些宏观意见的，“PS不够吸引人”，“motivation 不够强”等。如果你的老师，朋友，同学给出这样的意见，那就多问他们一句，如果需要修改，具体需要替换哪几个例子，哪些不分需要重写，怎么写。只有给出实实在在修改意见的人才是有帮助的。
耶鲁的建议
When you write your essays and “short takes” for the Common Application and Yale-specific questions, write about something that matters to you. Use your own voice. Do not worry about making a special effort to include impressive vocabulary words or overly complex sentences. If you sound like yourself and discuss something you care about, your essay will be more effective.
We know that no one can fit an entire life story into two brief essays, and we don’t expect you to try. Pick two topics that will give us an idea of who you are. It doesn’t matter which topics you choose, as long as they are meaningful to you. We have read wonderful essays on common topics and weak essays on highly unusual ones. Your perspective – the lens through which you view your topic – is far more important than the specific topic itself. In the past, students have written about family situations, ethnicity or culture, school or community events to which they have had strong reactions, people who have influenced them, significant experiences, intellectual interests, personal aspirations, or – more generally – topics that spring from the life of the imagination.
Finally: proofread, proofread, proofread! Share your essays with at least one or two people who know you well – such as a parent, teacher, counselor, or friend – and ask for feedback. Remember that you ultimately have control over your essays, and your essays should retain your own voice, but others may be able to catch mistakes that you missed and help suggest areas to cut if you are over the word limit.*(1)
简单翻译要点如下：
（1）自己写，别纠结于那些没用的词汇与句型。
（2）做你做自己，但要有重点，不需要试图用一两篇文章把你的一生都写出来，我们明白这做不到（我们也不是傻子不是？）。
（3）话题无所谓平常与新奇，平常的话题可以写出很棒的ESSAY，新奇的话题也可以写得狗屁不是。
（4）别太长。
（5）校正，校正、再校正！但别矫枉过正！
资料下载
- 哈佛大学成功申请ESSAY五十篇整理（第三版）(PDF)
- 哈佛大学成功申请ESSAY五十篇整理（第一版）(PDF)
- 常春藤名校申请成功ESSAY五十篇整理(PDF)
- 经典Essay译文汇
参考资料：
(1) Advice on Putting Together Your Application-Essay Yale University