Step 1:
I taped three standard printer / copy papers together to get one large folding paper for the dress.
Prefold in half

Step 6:
Fold over the prefolded lines

Step 5:
Fold over this line.

Step 2:
Prefold the edges to the centerline

Step 4:
Prefold, then unfold the model

Step 3:
Fold in half over the prefolded line

Step 10:
Take a nice fashion doll

Step 8:
Fold over this line

Step 9:
Fold on both corners, then turn the model

Step 7:
Fold over the prefolded lines

Step 16:
This is the dress from behind.

Step 15:
Take / make a paper strip to use as belt.
Tie the strip around the waist.

Step 12:
Press the dress inwards around the waist

Step 11:
Tape / glue both edges together

Step 14:
This is how the dress should look.

Step 13:
Press the part between the arrows inwards