Dampen the tutu material with a little water in a spray bottle. Spray the tutu skirt with just enough water to allow the material to be slightly damp.
Spray the tutu material with the spray starch, making an even layer over all of the fabric. Be careful not to swamp the material in the starch material. Ideally, the starch should create a damp veil over the tutu tulle.
Hang the tutu upside down on a hanger. Use the material at the crotch of the tutu and place a pinch of fabric inside two clothespins. Attach the clothespins to the hanger. Allow the tutu to dry completely before removing it from the hanger. The starch should stiffen the fabric, and the hanging will ensure the fabric stays straight.