Irons, to their credit, do spell things out for us (what with an aptly labeled "silk" setting for silk and all). So how come our cotton sheets are always creased, and our polyester tops have a weird sheen post-press? Here, a handy guide to ironing all your belongings like a boss.
Cotton: Iron on high heat while the cloth is still damp to the touch. Use the steam and spray buttons generously as needed.
Linen: Iron the garment inside out on high heat while the cloth is still damp to the touch. Use the steam and spray buttons generously/as needed.
Wool: Iron the garment inside out on medium-low heat, and use steam to dampen. (Iron onto a pressing cloth if desired, as an extra layer of caution.)