There are a couple of options you could consider. In the course that you would like to copy, click on Settings in the course navigation, then on the far right you can click the link to Export Course Content.

This will create a course package and save it to your computer. In the new course, click again on Settings in the course navigation and then click Import Course Content. Search for the course file on your computer and upload it.
Alternatively, you can export your course to Canvas Commons and then import it that way. Once again in the course Settings page, in the upper right corner is a link to share to commons.