Turn off the electricity that goes to the garbage disposal. Flip the socket for the kitchen to be safe.
Reach into the garbage disposal using a pair of pliers to remove any visible material from the garbage disposal. Turn on the power and test.
Turn off the power to the garbage disposal again if the clog isn't removed.
Set up a flashlight under the sink so that it points toward the bottom of the garbage disposal.
Insert an Allen wrench into the bottom of the garbage disposal and turn it both clockwise and counterclockwise until it can make a full revolution to remove the clog. Turn on the electricity and test again.
Stuff a rag into the overflow hole for the sink if it still will not drain. Place a plunger over the drain hole and plunge 15 to 20 times. The sink should drain.