Now that you have your essay written, you need to spend some time proofreading. There is no one method for proofreading that will guarantee you will find all the mistakes, or inconsistencies. The basic principle is to start with organization and content. Then spend some time examining sentence structure, word choices, spelling, and punctuation.
In this video blog I talk about two important things you need to know on a writing test. The first one is understanding and responding to the topic itself, and the second one is how to develop your ideas into a well organized paragraph.
Rule: Use "a" before words that begin with a CONSONANT SOUND and "an" before words that begin with a VOWEL SOUND. But there are exceptions.
When writing compound sentences, use a comma before the coordinating conjunction.