Store avocados at room temperature to ripen, and once they are ripe, refrigerate them.
If you want them to ripen them faster, place them in a paper bag with an apple or banana.
For cut avocados, leave the stone in, wrap them tightly in cling wrap and store them in the fridge. Placing them in an air-tight container also works well.
To freeze avocado, mash or puree the flesh with a little lemon juice and then freeze in a small container, bag or ice cube tray.