The main actions you can take are

(1) to instruct or teach the reader something;

(2) to delight the reader, or to give the reader something to appreciate or enjoy;

(3) to move the reader, which means to inspire the reader to feel a certain way or to go out and do something.

http://www.gradesaver.com/resources/goodessay.html

Here is a website that give specific examples of good and bad

http://kimberlychapman.com/essay/badwriting.html

Finally, another one that gives examples

http://www.essaymall.com/Example_essay.php

Don’t have any examples to give, but generally, a good essay has direction. It starts with a good thesis statement at the end of the first paragraph, or the first paragraph itself which states the purpose of the essay. The following paragraphs should carry out what was stated at the beginning. A good essay sticks with this purpose throughout the essay and doesn’t ever stray very far off course. While writing, constantly ask yourself whether your answering the question asked, or sticking to the topic. Also never write “I” or “You” in an essay unless the prompt addresses what YOU think about something. Even then try to keep them to a minimum.