Everyone loves a comfy cotton shirt, but 100% cotton is actually quite sensitive to shrinkage. Be sure to wash your cotton clothing in cold water, and give it a gentle tug when the wash cycle ends. Cotton blends will hold up in the dryer, but always airdry 100% cotton items.
Denim seems tough, but it requires special care if you want that go-to pair of jeans to last for years. Always wash new jeans separately for the first few rounds of laundry to ensure the dye doesn't bleed onto other items. It's also best to turn them inside out. Wash jeans in cold water to mitigate pilling and fading. Finally, pull your jeans from the dryer when they're still a tad damp to preserve their lifespan.
Consider spandex much like your intimates, since the fibers of a spandex blend are prone to stretching and tearing. Use the delicate or gentle cycle for spandex, and wash in warm water. It's also a good idea to throw your spandex items into a mesh garment bag before putting them in the machine to preserve the elasticity on bands.
Only put silk in your washing machine if the label allows it, and always use the delicate cycle! Silk with color in it is prone to bleeding, so definitely keep your silk clothing separate and treat it with extra care.