Plug in the iron and turn its heat setting to low or medium. If the iron has a "Polyester" setting, use this setting.
Lay the polyester garment out flat on the ironing board.
Press the flat side of the iron against the garment and hold it in place for a few seconds before pressing it against a new location. Work your way around the entire garment until all wrinkles are removed. Lightly spray very wrinkled areas with the water bottle before ironing.
Use a pressing cloth for sensitive garments. Lay the pressing cloth over the area to be ironed and press the iron against the cloth. This avoids direct contact with the iron.