hanky be flat in order to make a bonnet that looks good.
fold one side of edge of the handkerchief over about an inch and a half. press the fold with the iron.
use the needle and thread to take large stitches along this folded edge. instead of tying off the thread at the end, gently pull thread to gather the fabric into a rough bonnet shape. take a few stitches to secure the two ends of the gathered edge.
fold the straight edge of the hanky back until it is the correct size for a bonnet. the amount you fold back will depend on the size of the hanky you are using. 