By default, your Clipps are chronologically ordered with the most recent appearing at the top. You can use drag and drop to reorder the Clipps within their Clippboard. (Just mouse over the header of the Clipp you want to move, hold down the left button on your mouse while you drag it to the desired position, and let go.)
Please note: Drag and drop does not work in Internet Explorer 8.
You can also use the Stick to Top tool (click the gear in the Clipp header) to stick one Clipp to the first position within that Clippboard.
If your Clippboard is collaborative, only the Clippboard owner will be able to drag and drop, and all collaborators will see the order set by the owner.
Watch a video about reordering your Clipps.