After all is said and done, what you write will be your best or worst credential. Your essays are extremely important. Think what you write. Show a logical progression. With the English language -at least in America-, "more is less", meaning that less clutter and making a point while being grammatically correct is highly valued. Essays are a good opportunity to explain unforeseen events that have occurred in your life, and they can influence a reader towards a positive decision on your application. Do not lie, report facts and circumstances that have affected you, or major accomplishments worth noting. Universities always check, and lies are hard to keep up with.
If English is your second language
In searching for the truth you need to ask yourself the following questions: First: Am I a good reader, listener and writer of English?. In reality, where do I stand in each of those areas?. If I were to sit in a classroom at an American University how would I perform?. The bottom line is; you need to find out if you can follow a lecture on an academic topic at university level. This should include the necessary give and take to answer questions, participate in class discussion, and produce original papers. If you have not done so, you need to take a TOEFL test as soon as possible to have a first unbiased measure of your ability. The test will also serve as a measure of future progress.
As a norm, I would seriously recommend to view a TOEFL score of 660 as a mark that will guarantee some degree of confidence on the ability to keep up with the daily demands of university studies. Many Colleges such as Endicott College, in Beverly, Massachusetts accept students with TOEFL scores around the 600 mark, requiring participation in their English as a Second Language Program, as a precondition for admission. This important step allows students to combine ESL instruction with academic courses. The obvious advantage is that it does not delay admission to a program of study...