There’s a lot of space above the shelf in most closets. Even though it’s a little hard to reach, it’s a great place to store seldom-used items. Make use of this wasted space by adding a second shelf above the existing one. Buy enough closet shelving material to match the length of the existing shelf plus enough for two end supports and middle supports over each bracket. Twelve-inch-wide shelving is available in various lengths and finishes at home centers and lumberyards.
You can also use Google image search to research a project. Unlike the PDF search, the image search provides a photo of what the project will look like, which is helpful in determining if you want to pursue building it. By doing an image search for how to build a step stool, you will have a ton of options that all lead to woodworking plans of various quality. (The how to part of these is important—otherwise you’ll just get pictures of step stools.)