To cut open an avocado, slice the avocado
in half by cutting around it lengthwise down to the pit. Then twist each half in opposite directions. The avocado should pop open. If only using half of an avocado, store the half that has the pit in it. Wrap it in plastic and store in the refrigerator. The pit will help slow down the discoloration. If the cut edge does become discolored, it can be cut off and the fruit underneath will be usable.
When selecting avocados, depress the outer skin lightly, if it is ripe it should be soft to the touch and depress easily, but should not be mushy. Unripe avocados can be ripened by placing them in an open area at room temperature for a week or for faster ripening, wrap them in newspaper or a brown bag and keep them at room temperature for several days.