Fold over elastic is easier than I thought. I already failed once - many years ago - but also failed to make a search on how to do it.
Finally I figured out how to do it - here are some useful tips on how to sew.
The pattern I used for my project was So Sew Easy´s Empire of the Sun Dress which is a free pattern. The pattern comes in a layered format. It´s worth to go through the instructions on how to print it as it´s becoming common with download-patterns and saves time when assembling and cutting the pattern.
I used a medium weight viscose jersey and needed about 2m-s. I think it would even work nicer with something which has a busy pattern - that covers up the elastic casing which is very visible on mine. A lighter fabric would make it more drapey.
It´s a great dress - front and back are identical.
I also gave away a big bag of scraps and fabrics I´ll never use for charity. Now I can fill up the space again with great new stuff :)