For this slouchy short dress start with a simple pattern or draft from another stretchy dress you have.
Drafting option: fold your dress in half, put it on a large piece of newsprint paper (or even news paper but use a sharpie so you can see the lines) and grade sides / sleeves up. You may also want to consider a larger neck opening if you want it to be able to drop down the shoulders as seen here.
You will also need to draft the facing / stretch band around the neckline (make this a bit smaller than the opening so you can sew it up stretched ~2″ – 3″ shorter).
Step 1: Cutting Fabric
Pin the pattern to the fabric folded in half along the grainline and then chalk the edges. You will need to cut 2 pieces for the front and back.
Then cut the facing from your pattern.
Step 2: Sew the side seams
Pin and sew the side seams down with a 1/2″ zig zag stitch (2mm in length and 1.5mm width) this will allow the threads not to break when stretched. (Be sure to use a ballpoint needle as well, a size 14 would be good for most non-sheer fabrics)
Step 3: Serged finishings
Now serge the seams together (closed and not flat open for stretch) on the wrong side (if your fabric frays, i.e. non-double knits will typically need this). Also serge around the hem of the dress and the arm hole openings so those ends do not fray.
Step 4: Hem and top stitch hem and armholes
For the Hem and armhole, you can do a simple 1″ – 1.5″ fold-up (depending on how much extra you left on your pattern for the hems), pin and then top stitch down with a straight 2mm stitch.
Step 5: Treating the neck knit binding
For neckline, fold the facing fabric (1.75″ – 2″ in height) in half (with the good sides on the outsides) and iron it to create the crease. Then stitch the ends together to create a band (1/4″ seam for the ends).
Step 6: Sewing and finishing the neck knit binding
Afterwards, put a pin at equal quarters along the band as well as the neck opening of the dress (on the wrong side) and match them up (this will ensure it’s slightly stretched evenly). The band should be pinned to the neckline with the raw edges matching and pin through all 3 layers.
Use a small straight stitch (same settings as above) and sew the neckband to the neckhole with a 1/4″, stretching a bit as you sew.
Now serge the raw edge and then put in a top stitch (follow closely or 1/4 ” from the new opening) to make sure the band stays inside the neck opening and do not flap up.
Try it out!
Add a belt to your slouchy dress and you can wear it many ways!