Imagine an adventurer who wishes to explore a chain of islands. His journey will be an easy one if the islands are connected by bridges, but it becomes significantly more difficult if he must swim from one to the other. Your paragraphs are like these islands and your reader like the adventurer. You must use transitions as bridges that connect one paragraph to the next; otherwise, your reader will struggle to move between the points of your argument and your essay will lack "flow," the hallmark of good writing.
The first sentence of your paragraph should provide a smooth transition between the previous paragraph and the current one by showing how the ideas presented in each are connected or related. If you spent the time to construct an appropriate outline where your ideas follow and build on one another naturally, then the organization you established there should make your transitions clear. Also, look to the closing observation of the previous paragraph for inspiration on how to phrase your transition.
When building your transitions, ask yourself: How are the paragraphs linked? Do additional connections need to be identified? If you have difficulty showing the relationship between your paragraphs, it may be symptomatic of a weak organizational structure. Go back to your outline and make sure that it presents a logical progression between your main points. If a good flow to your writing isn't apparent to you, then it certainly won't be to your readers.
Tell a Story
Telling a story is a common and effective way for catching and keeping the reader's interest. This approach can be applied to a variety of circumstances as the story can span a lifetime or a single event. It also doesn't need to be filled with the type of action you'd see in a summer blockbuster because even the briefest and simplest of events can take on meaning when told effectively. Just remember that it is not enough to simply tell a story. You must also draw a connection between your story and your motivation/qualifications for attending medical school.
Remember, the personal statement is the one area of your application where you can infuse a little bit of personality. Your goal is to make yourself a "real person" to the admissions committee and not just an "academic profile." Using your life story to illustrate the points you are trying to make is an excellent way of doing this.
When writing your story, stay informal and conversational. Many applicants try so hard to sound impressive to the admissions committee that their writing style become stilted and artificial. These applicants wind up portraying themselves as overstuffed, pompous characters no committee member would want to spend much time with, instead of real people with goals and ideals.
Details and Conciseness
Show, don't tell, who you are by backing up your claims with real experiences. Be specific! Each and every point that you make needs to be supported by examples and scenarios taken from your life. It is these details that make your story unique, interesting, and personal. Yet, at the same time, don't go overboard with too many details. After all, you only have one page to write. You must resist the temptation to pad; one way to find out whether you are successful is to delete parts and ask yourself whether you have lost any meaning. In your first draft, feel free to write as much as you want. Then, go back and take out unnecessary details. Only say as much as you need to say to get your point across.
Also, avoid redundancies. In the limited space you have, every sentence should offer something new, not rehash what you've already said. Do not keep repeating the same thing over and over again in different words thinking that it will emphasize the point. It just makes your statement boring, and you lose your readers, most of whom have just a few minutes to spend on your entire application. If you don't get their interest and sustain it, you lose.
Word Choice and Sentence Structure
When writing your essay, pay attention to the words and sentences you use. Don't use a thesaurus to make yourself look smarter because it will only make it seem like you are trying to sound smarter. Just use your normal vocabulary as this will sound more natural and preserve your voice in the essay. If you do use a thesaurus, make sure you know the exact definitions of the words you're using as well as their connotations.
Try to keep adjectives and adverbs to a minimum. Instead, focus on using active verbs.
Vary your sentence length and structure to add additional interest and greater impact. Not all of your sentences need to be long and complex. A good mix of short and sweet ones can really add some spice to your essay.