One good way to get involved in the OpenStreetMap project is to upload GPS track logs, also known as GPS traces. Recorded by your GPS device, the typical trace is a record of your location every second, or every meter. The resulting file will be a series of dots that show the path of where you have been.
They can be added to the background of the editing map as thin lines or little dots. These lines and dots can then be used to help you add map features, similar to using aerial imagery.
For more information on using GPS devices and converting the trace to a GPX file see Recording GPS tracks and Upload GPS tracks. Note that uploading GPS traces is a different process than editing the map, and is also different from bulk imports.