Choose a counter top that does not receive any direct sun. You can turn it once a day. But the main component is patience. Some will never ripen for having been frozen or otherwise mistreated in getting it to you.
The best and quickest way to ripen an avocado would be to place it in a brown paper bag. This technique also works well with peaches, nectarines, and mangoes.
In order to ripen an avocado in the best way to insure flavor, take the semi-ripened or non-ripe fruit and place it into a small paper bag. Place the bag in your window seal where it will not be to hot and leave alone for a few days until ripe.
