Decide what problem to write about. Think about an issue that the audience will be able to relate to and try to keep it as broad and simple as possible. For example, instead of going into detail about why the school's basketball team keeps losing, focus on one aspect with a clear-cut solution, like how practice time needs to be longer. State the problem clearly in the introduction paragraph.
The second paragraph should explain what the problem is, who it affects, why it is an issue and other details that help the reader understand why a solution must be found. Try to be descriptive and informative, and be sure to offer supporting evidence. For instance, if the problem is that backpacks are too heavy, include an anecdote, or story, about a classmate who hurt her back, or a statistic about how much weight middle school students should carry on their shoulders.
The reader will want to see that the writer has considered several possible solutions, before settling on one answer to the problem. Spend about two or three paragraphs, laying out ideas that could solve the problem that has been stated. Describe the advantages and disadvantages to each possible solution. Try to include transitions between paragraphs to keep a nice flow to the essay. Remember that the ultimate goal is to persuade the reader to get behind the final solution.
End the essay strong, with a lot of supporting evidence that convinces the reader that the proposed solution is the best of all possible solutions. Write about what advantages the final solution has, that the other solutions did not resolve. For example, if the best solution to lack of sleep is going to bed earlier, explain why an earlier bedtime is better than napping after school. End the essay by restating the problem and using simple and strong language to prove how the solution will help.