Here are some steps you can try:

1. Check for obstructions: The first thing you should do is check the dishwasher for any obstructions that may be blocking the drain. Remove any food scraps or other debris that may be blocking the drain.

2. Check the air gap: Many dishwashers have an air gap located on the sink or countertop that prevents backflow from the drain into the dishwasher. If the air gap is clogged, it can prevent the dishwasher from draining properly. Remove the air gap cap and clean out any debris.

3. Check the drain hose: The drain hose may be clogged or kinked, preventing water from draining out of the dishwasher. Check to make sure the drain hose is not kinked or obstructed in any way. If it is, try straightening it out or removing any obstructions.

4. Check the garbage disposal: If your dishwasher is connected to a garbage disposal, make sure it is not clogged. Run the garbage disposal to clear any debris that may be blocking the drain.

5. Run a cycle with vinegar: Sometimes, a buildup of grease or mineral deposits can cause the dishwasher to drain slowly or not at all. Run a cycle with white vinegar to help break up any buildup and clean out the drain.

6. Check the pump: If none of these steps solve the problem, the issue may be with the dishwasher's pump. In this case, it's best to contact a professional technician to diagnose and repair the problem.

Remember, before attempting any repairs on your dishwasher, make sure the power is turned off and the unit is unplugged to prevent any potential electric shock.