Here are some tips to write essay for admission in well-reputed universities and colleges.

Collect points
Collect point on which you want to focus on. Note down the important points and start writing.

Be concise
Write your essay concisely. Don’t try to elaborate your essay unnecessarily.

Include extra information
Don’t just give the common information. Try supplying information which the reader doesn’t expect.

Include extraordinary ideas
In your essay, include extraordinary ideas. Your ideas must impress the admission staffs.

Prove your ideas
Prove the points you’ve mentioned with different examples.

Explain why this course is important for you
Include why the course you’ve chosen is important for you. Write down why you’ve selected this course.

Proof read your essay
Once you complete writing your essay, read it yourself to find out errors and to make some modifications.

Let others read your essay
Once you’ve completed writing, let others read it out. Ask them to find out errors and to suggest you to improve some points.

Filter your information with resume
Don’t include information from your resume. Try not to mention information about your studies and work experiences in an essay.

Be quite humorous
Making your essay quite humorous will work. But remember, don’t make it too humorous.

I found some tips on writing an essay for Admission at Carleton College's website which is available here:

http://apps.carleton.edu/admissions/counselors/essay/

Stanford's Guideline for admission essays:
http://www.gsb.stanford.edu/mba/admission/essays_activities.html

University of Washington tips for admission essays:
http://www.son.washington.edu/eo/info_masters_essay_tips.asp

Essay writing tips from Foothill College:
http://www.foothill.edu/transfer/essay.html

Tips from Santa Ana College:
http://www.sac.edu/students/library/nealley/pathfinders/meb_essay.htm

Graduate Application Tips from Iowa State University:
http://www.psychology.iastate.edu/index.php?id=76

It think going through any of these tips will help you write good essay for admission application.

I hope my answer helped you.

1. Transferring from Community College to University
2. Is it possible to study abroad?
3. Studying Masters in Computer Networking or Security in UK with 5.5 in IELTS
4. Help in selecting a college for MS in Computer Science
5. List of Universities for Telecommunication in Australia, Canada and Sweden
6. Studying in Netherlands without IELTS after completing Computer Science and Engineering
7. How can I get admission in Swedish Universities?
8. When can I apply for Masters in Environment Management Program?
9. Can I join a Masters Program in USA if I have TOEFL PBT score 523 and BEng (Marine)?
10. Can I apply for ACCA in UK universities?
11. Chance for Admission and Course Suggestions for Electrical Engineer with 5.5 Years Work Experience
12. Admission at any European University without TOEFL
13. Requirements for PhD in Biotech from Germany
14. Requirements for Bachelor Degree Program in Engineering
15. Can I get admission into an Aeronautical Engg program with poor High school grades?