Self-made garments: ultra fine jersey tank with french seams and low gathered back | black wool skirt with adjustable fit
Separate gathers can be zipped onto the skirt like this one. there are also little gaps in the seams for a belt to be weaved in and cinch at certain places. Unzipping the back allows it to be worn lower on the hip.
You can see more of the things i have made here.
image source: personal photographs