Use a liquid, phosphate-free, concentrated detergent. Measure per the instructions.
Sort laundry first by weight. For example, jeans, towels, and sweats go in the heavy load; button up shirts, underwear, and dress socks go in the light load. T-shirts, collared, knit shirts, and sports socks can go either way. If you have enough volume, also sort by color.
Wash full loads but don’t overfill.
Wash in cold water.
If there’s a lint trap, clean it regularly.
If the washer hoses are rubber, check them every couple of years and replace as needed – preferably with braided-steel.
Line dry inside or outside if you have the space. (Inside possibilities include spare closet rods and towel racks.)
If you have to machine dry, keep like weights together, use a moderate temperature, and use the dryness sensor (set to ‘Less Dry’) rather than the timer. Air dry any clothes that are still slightly damp.
Clean the dryer lint trap after every load.