Here are some ideas: You are stranded on an Island for 3 days, your only resources are those found in the overwhelmingly beautiful landscape. Your eyes are two different colours, one blue and one green, the green eye sees truth, but the brown eye sees much much more. You are the most famous 3rd Grader in the world. Also, the book Writing Magic is lovely for Imaginative or Fantasy essays, stories, and books!
Supporting details are reasons, examples, facts, steps, or other kinds of evidence that explain the main idea. Major details explain and develop the main idea.