To finish the upper edge of the doll dress, or the waistband of the doll skirt, bias binding tape or ribbon will be sewn to the upper edge and folded over the edge to cover the raw gathered edge of the fabric. If you are a beginning sewer, bias binding tape is the easiest material to use as it stretches when on the doll to fit the skirt or dress better. If you prefer, you can substitute a piece of ribbon which you fold over the edge to finish it. If you use ribbon, use a thin ribbon rather than a heavy one, and choose a ribbon which is easy to fold in half.
Line your ribbon or bias tape so the upper edge of the inside of the partially unfolded bias tape (the main fold is opened up, but the folds for the edges are left (see photo) lines up with the upper edge of your fabric. You want the finished edge of the tape or ribbon (the 'good' or 'right' side), to face towards the 'right' side of your fabric (the printed side). In the photo above, if you were using ribbon, the 'good' side of the ribbon would not be showing, it would be pressed against the 'good' or printed side of the fabric.
Cut your bias tape or ribbon so you have 1/4 inch extra length on either side of your fabric. Pin the tape or ribbon to the fabric with sewing pins as shown.