Place bananas in a paper bag
Add an apple or ripe avocado to the bag
Fold the top of the bag loosely closed
Keep the bag at room temperature
Store bananas near other ripe fruit
Separate bananas from the bunch if you want them to ripen faster individually
Wrap the stems with plastic wrap to help trap ethylene gas
Put bananas in a warm spot away from direct sunlight
Check them daily until they reach the desired ripeness
Use an oven only if you need very soft bananas for baking
Use a microwave only for immediate softening, not true ripening