Stan and I love steamed artichokes. Here's how I prepare them.
At the store:
Choose artichokes that seem heavy for their size. Purple discoloration on the petals just means it was exposed to a frost, but do make sure the stem doesn't show any signs of mold or rot.
Rinse well and cut off stem at base. Cut off top 1/4 and trim petal tips with scissors (I don't always do this, but it makes them pretty and less "pokey").
Stand, stem up, in 1-2" of water in a pot (arrange so they hold each other in place). Add some crushed garlic, salt and lemon juice. Bring to a gentle boil with lid slanted so that some steam can escape. Cook until tender, test by pushing a butter knife thru the base - if it goes all the way in, you're done. Usually, 30-45 minutes.
Use tongs to pull them out and turn them petal-side up. Dip in garlic butter or mayo and scrape the meat off with your teeth. When you get to the "choke", scrape it off with a spoon and enjoy the heart. I buy 1 artichoke for each of us.