An elastic waistband is an easy way to add shaping to a loose fit dress. The Creative Sewist has a tutorial showing how. There are step by step instructions as well as a video showing what to do. This works with any length dress, from maxi dresses to shorter dresses.
[photo from The Creative Sewist]
I can’t find a link to the tutorial.
So sorry about that! I forgot to add that part in. I’ve got it corrected now. –Anne