Check the water temperature. Should be 125 to 140 F.
Check pump re-circulation., Listen, see if it sounds like it is spraying the water around with enough pressure.
Check water level when the fill cycle has completed. Should be just under the heating element. If not, possibly need to replace the water inlet valve.
Check the spray arm and pump cover for splits or leaks.
Check to make sure dishwasher is draining after each cycle. There should only be a little water in the bottom of the tub.
Make sure the dishes are loaded properly, or dishwasher is not overloaded.
Possibly try a different detergent. Some liquid-gels will bubble and a pump cannot pump bubbles.