The method I use is to firmly grab the top at the base and twist it out of teh pineapple. Then you peel off the bottom leaves to revel the root stubs. Let it dry overnight, then sit it in a glas of water. replace the water every week or so and let it do its thing. once the roots are about half an inch long, pot it into a cacti and succulent mix. Hasn't failed yet.

Is there anything special about choosing the pineapple?

When selecting one to propagate, does the ripeness matter? Green/under ripe to Golden/over ripe?

When I look down in the center of the leaves, does the condition of the newest ones make a difference? Sometimes they are dark green, other times they are yellowed. Sometimes they are firm, other times they pull out easily. Does it matter?

It is important when using a store bought pineapple that the pineapple is not too old. It is hard to tell how long it has been since the pineapple has been picked. You want to buy one that is ripe but make sure there is no brown edges and looks fresh. If you peal the leaves and find roots and they don't grow when put in water then the pineapple was too old and basically dead.