For an introduction to writing the first sentence of an essay, see "The First Sentence" under Academic Essays. For an introduction to the different kinds of paths your essay might follow, see "Take Your Reader on a Trip" on the same page.
The first draft of your first sentence should be just enough to get you started as you begin to write. Later, after you have a good command of your topic and have a good sense of the overall tone of your essay--this may not be until after you have written several drafts--you can spend time focusing on the first sentence. This point in your writing is a good time to go back to sample essays to see what they accomplish in the first sentence. Does one of them provide a model for a sentence that would work well in your essay?
If you are having trouble structuring your essay, one good strategy is to look through everything you have written for the one best or most moving line. Try putting that sentence at the start and forming the rest of the essay around that primary idea. Note that this line might be the last point chronologically in your narrative--putting it first would give the whole essay an interesting "flashback" structure.
Here are some sample openings that might fit your essay.
1. Dialogue. Dialogue usually gets a reader's attention. This is because dialogue gives a sense of present action. Even one sentence in quotation marks can be enough. Example: "'I don't know where you get those ideas!' my mother said. I was drawing and explaining my latest, perhaps my craziest, back-of-the-placemat 'invention'..." This opening shows that the writer is thoughtful yet aware of the limitations of his ideas, friendly with his mom, and perhaps just the kind of person who can learn to focus his ideas with a good college education.
2. A short, striking sentence. Readers often appreciate writers who can pack a punch and then mellow out. You can be dramatic without being melodramatic. Example: "I held my gun firmly. The paintball field was covered in blue, yellow, and red splotches..."
3. A leisurely introduction. If the essay isn't action-packed but instead paints a beautiful picture for the reader, let the opening suggest a pleasant experience. Example: "Rowing out to the island on Lake Bled, dwarfed by the Slovenian Alps to the north and by an ancient castle high on the eastern hill, I was enjoying the best day of my summer vacation." Take the reader with you through this wonderful experience, using extra phrases and clauses beyond the simple subject and verb of the sentence.
4. A challenge. You can draw the reader into your argument if you advertise that you have learned something that goes against common knowledge. Perhaps you figured out that cats actually love to be petted the "wrong" way, back to front. Example: "Although my parents had warned me never to pet a cat from back to front, I recently discovered that Stitches can't get enough of my 'backward' attentions." This sentence suggests that the writer is willing to challenge cultural norms, which a lot of colleges want to see their students learn to do. Note that this kind of opening frequently starts out with the common knowledge but adds a challenging word such as although, but, while, or even though somewhere in the first clause, and then suggests the content of the challenge in the second clause.
5. A warning. A reader will pay attention when there is something to be concerned about. Examples: "I wish someone had told me two years ago that sometimes a pool of water on the road is really a mirage!" "When I worked for Representative Smith's political campaign last summer, I learned that pollution from factories in our state is far less of a danger to public health than runoff from farms." The second example shows that the writer knows something that readers should be aware of, that the writer did some interesting work, and that the writer learned something valuable from the experience.