My style of washing denim is the following. When you receive your pair of denim, they will be raw. For the complete shrinkage, machine wash in warm-hot water to get the maximum shrinkage and then hang dry. When you try them on , if they are still too big, machine wash again in warmer water and then dry in dryer for complete shrinkage.
For future care after the original wash, you want to machine wash cool and then line dry. Line/ Hang dry will create more texture and keep the denim looking good. Before line/ hang dry, pull denim taut and shape it before hanging it up.