1. Make Sure Options 1 Through 5 Aren't Appropriate
I've rarely seen an admissions essay that doesn't fit into one of the first five Common Application essay options. Even the sample essay by Lora
which she submitted under option #6 could fit into option #1. In truth, it probably doesn't matter much if you write your essay under option #6 when it could fit elsewhere (unless the fit with another option is obvious) -- it's the quality of the essay that most matters.
2. Don't Try Too Hard To Be CleverSome students make the mistake of assuming that "Topic of Your Choice" means that they can write about anything. Keep in mind that the admissions officers take the essay seriously, so you should too. This doesn't mean you can't be humorous, but you do need to make sure your essay has substance. If your essay focuses more on a good laugh than on revealing why you'd make a good college student, you should rethink your approach.
3. Make Sure Your Essay Is An Essay (No Poems, Drawings, etc.)Every now and then a budding creative writer decides to submit a poem, play or other creative work for essay option #6. Don't do it. The Common Application allows for supplemental materials, so you should include your creative work there. The essay should be an essay -- non-fiction prose that explores a topic and reveals your character.
4. Reveal YourselfAny topic is a possibility for option #6, but you want to make sure your writing fulfills the purpose of the admissions essay. The college admissions folks are looking for evidence that you'll make a good campus citizen. Your essay should reveal your character, values, personality, beliefs and (if appropriate) sense of humor. You want your reader to end your essay thinking, "Yes, this is someone who I want to live in my community."