To improve your writing you need to make sure that your ideas, both in sentences and paragraphs, stick together or have coherence and that the gap between ideas is bridged smoothly. One way to do this is by using transitions - words or phrases or techniques that help bring two ideas together. Transitional words and phrases represent one way of gaining coherence. Certain words help continue an idea, indicate a shift of though or contrast, or sum up a conclusion. Check the following list of words to find those that will pull your sentences and paragraphs together.
Some applicants may ramble on about themselves in a manner that may appear self-indulgent and not very appealing to the committee. Remember, this is an application essay, not an autobiography. Conversely, some applicants tend to say too little, perhaps hesitating to promote themselves too explicitly or not knowing what about themselves would be interesting to people whom they don't know. In such cases, perhaps focusing more on what you want to do than on what you have already done (let your record speak for itself) may help in getting beyond self-inhibition.