The easiest way to create a good ending for expository writing is to focus on the introduction. Early on, writers typically include a thesis statement, or main idea, to be discussed. For the conclusion, you can return to the main idea and rephrase it concisely, in different words from the original.
The introduction and conclusion in a piece of expository writing are usually about the same length. The body, which proves or supports the main idea, offers depth and width on the topic. If you are writing a how-to or other practical guidance, you probably don't even need a conclusion. Simply present your points.
You will probably have several paragraphs devoted to each point in the body of an expository document. Effective conclusions can summarize those points, reminding readers of what they just read. The summary should be concise.
When readers come to the end of your expository document, they should know they have arrived at a conclusion. The work should feel complete. The easiest way to do this is to offer readers a few closing words suggesting they do something. For example, you might ask them to write to a local representative or start recycling program.