Making sketches of objects is a very effective way of communicating your ideas about shapes. This skill is one that anybody can build, and the more you draw, the better you will get at it.
To do these drawings, you just need a pencil and a piece of paper. An eraser is nice, but not essential.
The main drawing techniques for engineering are: Orthographic, Isometric, and Multi View Orthographic. By drawing an object using one or more of these techniques, you can communicate quite a bit about the shape, and how the parts relate to each other. WISC-Online has an interactive set of images that help explain Orthographic and Multi View drawings. There is another for identifying Isometric drawings.
These techniques do not show Perspective, where the lines converge on a vanishing point. The lack of a vanishing point, and the presence of parallel lines means that the actual dimensions and proportions of the shapes can be shown. If you draw using these techniques of Orthographic and Isometric with greater accuracy, you can show the actual sizes or even scale dimensions of the objects. Having good drawings of your ideas will help you to share your thoughts with other people, and develop your designs before committing them to solid materials.
Drawing on the Right Side of the Brain by Betty Edwards has a number of good exercises in drawing, including these techniques. You may also find information about sketching in older books on drafting. Unfortunately, many newer books on Computer Aided Design and drafting seem to skip the skill of sketching.
Grab a pencil, a piece of paper, and look at some of the objects around you. Sketch them out, and develop your drawing skills.
There are photos of this project.