Rinse your dishes after eating. This Kris6 the food shmutz from turning into a crust you'll have to scour off and won't wash off completely in the dishwasher.
I used to live with people who actually refused to rinse their dishes when they were done.
One time, they tossed their salad Tupperware in the sink while it was sealed closed, and literally had like half the salad left in it. They didn't bother trying to throw it away when they were done with it at work, or when they got home. It was sitting there for a couple days by the time I went to do the dishes. Also they'd regularly invite friends over, cook them dinner, and then leave the dishes for me to do the next day.
Dish detergents actually need some food schmutz to work properly. I rinse stuff if it's particularly dirty or caked on, but only enough to get the big stuff off - I always leave a little schmutz. All my dishes come out perfectly clean.