Depending on what you need to copy, and you need to copy across a large number of courses, the Copy Course Bulk tool may be useful if it's available to you. Access to the Copy Course Bulk tool is normally restricted to users in the Administrator/Educational Developer type roles.
If you have a select number of components to copy from a course into others, and plan to use the Copy Course Bulk tool, a strategy I have seen used is to create a course offering with only the selected components you want copied into the other courses. Ensure the items are clearly named and identifiable so to not impact on existing content. For more information on this tool see
If you need to copy across a smaller number of courses e.g. <10-15 the Import/Export/Copy Components tool may be a quicker option. Remembering after you have initiated a copy using Import/Export/Copy Components you can move onto the next course and do not have to wait for the copy to complete.
Hope this helps!