A classic way to keep your delicates in good condition through the wash (besides a full load on the delicate setting) is to throw them in a mesh lingerie bag. Some items—like delicate sweaters, for example—often need to be washed by hand or dry cleaned to keep their softness and shape, so if your sweater requires dry cleaning or whatever, it’s best to follow those instructions; otherwise, though, putting your delicates in a mesh bag will give them a proper cleaning without the normal damage of a machine.
Also, things with velcro or hooks—like bras—often get snagged on other clothes in the washer and dryer. To prevent rips, tangles, and misshapen clothing, put those items in a mesh bag before you throw them in the washer and the dryer.