I made this dress from a black long-sleeved blouse and a long green skirt. I cut off a lot of fabric from the blouse, and sewed the two garments together about right under the bust. Then it was pretty much just trying on the new dress-in-progress a bunch of times and adjusting what I thought needed to be adjusted (darts, length adjustments etc.). There was originally a kind of belt (with buttons instead of a buckle) around the waist line of the skirt, sewn in the same fabric as the rest of the skirt, which I removed when attaching the skirt to the top. Afterwards, I cut off both ends of the belt (the buttons/buttonholes + around 5 cm), and sewed each end onto a fold in the fabric of the dress (skirt) in the back. Closing the buttons after pulling the dress over my head (I don't have the hang of zippers yet...) sort of tightens the fabric around the waist a bit, enabling a close fit.

There was a lot of leftover skirt fabric, some of it became the green flowers on the top. :-)

Old blouse + skirt