Not just humor, but the overall tone of your application essay is remarkably important. It's also difficult to get right. When you are asked to write about your accomplishments, those 750 words on how great you are can make you sound like a braggart. Be careful to balance your pride in your achievements with humility and generosity towards others. You also want to avoid sounding like a whiner -- use your essay to show off your skills, not to explain the injustices that lead to your low math score or failure to graduate #1 in your class.
There are two main ways to structure a problem-solution essay. These are similar to the ways to structure cause and effect essays , namely using a block or a chain structure. For the block structure, all of the problems are listed first, and all of the solutions are listed afterwards. For the chain structure, each problem is followed immediately by the solution to that problem. Both types of structure have their merits. The former is generally clearer, especially for shorter essays, while the latter ensures that any solutions you present relate directly to the problems you have given.
The Sacred Grove of Oshogbo was one place I had been looking forward to visiting in Nigeria. As prevalent as indigenous religions still are in West Africa, it is often hard to find public expressions of them in towns and cities; the Christianity brought by European slavers and colonialists has taken root and pushed most of these religions out of mainstream life. But in the Sacred Grove shrines honor all the local deities, including Obatala, the god of creation, Ogun, the god of iron, and Oshun, the goddess of water, whose aqueous essence is made manifest by the river running through the trees. The place is unique in the Yoruba religion, and that intrigued me.