the next method ... good for curvy, pointy pieces is as follows:
cut out the shape on freezer paper or from a manila folder. anything that will hold the shape during the whole process
cut out the shape from the fabric, leaving a generous seam allowance
make a small running stitch around the fabric. notice, please, that i pressed the points in before stitching
gather up the running stitch
fiddle with and flatten the piece ... press well from both sides ... back tack to hold it ... remove the paper