The wrong side will show so choose something that looks good on both sides. Drapy fabric is needed for the garment to look good. Chiffon or georgette is a good choice.
Fold the fabric in half along the length, and mark half way along this fold. Cut an opening from the front edge to this mark, by cutting about 1⁄4 to 1⁄2 inch from the fold, and curving to nothing at the top.
Finish all the edges of the garment, including the front opening. The best finish is an overlocker (serger) rolled hem. When sewing around the top of the front opening, hold the fabric gathered up so the stitching will continue around the curve at the top.
Lay the fabric out folded in half across the width, and with the front opening on top.
Bring the bottom point of one side pof the front opening across towards the other side, then fold it back the way it came, forming a sloping shoulder and a lapel.
Take the point at the back that has become visible and fold it forward to meet the front point, then down the bottom edge by about 4in. Pin the back edge to the edge at the bottom of the front overlapping by a scant 1/16 in.
Repeat this for the other side.
Close up of the overlap.
Sew the overlapped edges together.
Optional – sew beads to the remaining free points to help the garment drape correctly.
To wear, put your arms through the openings at the side, and ensure the free points are tucked behind the seams.