Copy and paste is all well and good, but it’s a four-step procedure. When you want to copy a region into a nearby spot, there’s a much more efficient technique: Option-dragging.
Press the Option key (called Alt on non-U.S. keyboards). While it’s down, drag a region to a new position. You peel off a perfect copy of the original. (You may recognize this technique from working with icons in the Finder.)
As with copy-and-paste, this feature is very useful when you drag horizontally, because:
Unlike looping, Option-dragging offers a quick and easy way to make a region repeat periodically, as opposed to immediately.
As noted earlier, Option-dragging creates a separate, fully independent region. That’s a handy tactic when you want to edit the copy or copies, creating slight variations from the original.
Option-dragging (or copy-and-paste, for that matter) is also useful when you drag a region vertically into a different track. For example, you can set up part doubling (two instruments playing the exact same notes) in a matter of seconds.