Here are the instructions for a flower bag. Bear in mind that the exact measurements are not at all important. I have made tiny ones of silk for keeping earrings in and large ones to use as lunch bags. This one is made of two layers of cotton but that is a bit heavy. A double sided fabric like batik, nicely hemmed would be better. I have also used thrift store scarves. Anything that is square will work.
I started with two 14.5 inch squares because that is the size of my square quilting ruler. I sewed them together, turned them and sewed around the edges so I wouldn't have to get out a needle and thread to sew up the opening.
Mark about 5 or 6 inches down from the point on each side and draw diagonal lines connecting the marks. Fold all these triangles to one side.
Sew across the angle. I used a half inch seam because I have only fairly thick yarn to use as a drawstring. On a tiny silk bag I would use a narrower seam and probably fine ribbon for drawstrings.
Thread in two drawstrings. I usually start from opposite sides. This is a very common thing in Japanese bags, but not so common over here.
Turn it over and pull up both drawstrings at once. Voila! A flower bag, all done.