Be sure to choose firm but ripe avocados. To determine if the fruit is ripe, hold it in the palm of your hand and very gently squeeze--the avocado should give slightly under gentle pressure. Color does not indicate ripeness and can range from light to dark green depending on the variety. To ripen hard avocados, place in a brown paper bag and store at room temperature for up to two days. Store soft fruit in the refrigerator to extend its life for two or three more days.