Ironing away from the collar points will avoid unsightly creasing at the front of the collar.
Natural fibers allow your skin to breathe, and shed moisture while synthetic fibers help the fabric to resist creasing.
One product I've found after trying so many on the market that really combats creasing eye shadows without fail from MAC Cosmetics is called Paints, and the shade I prefer because it works on almost every skin-tone is, "Untitled."
Shadow primers prevent creasing and help shadows to stay on longer.
Loose pigments are perfect if you want to achieve runway, high fashion looks without fading and creasing.