I took a class where we used a combination of freezer paper & undiluted starch, school glue & washable glue stick. It depended on the size and complexity of the shape which one was used. It's been a couple of years, but seems to me that the starch and a hot iron was used to coax sharp points into place before the applique was applied to the quilt. The glue stick was used for most pieces, with tiny dots of glue used for pointy or complex areas.