First step was to cut the jeans to the length of skirt that I wanted and then to cut down the inside leg seams.
Then I took the bottoms that I'd cut off and cut a piece to match the gap, which I then pinned to the wrong side of the skirt. The piece was then top-stitched in place. Lastly, I added a length of colourful fabric to the hem to brighten the skirt up a bit. Ta dah!
Not a great set of instructions or photos I know, but I just wanted to show you what I did.