First things first, look for a stem. If there is a stem on the cantaloupe (or any melon), put it down and keep looking. When melons are ripe, they snap away easily from the stem. If you see a stem on the fruit you want, then that fruit is probably not ripe and will not taste very good. The netting on the melon should be well defined and coarse. There should be a gold tint to the color of the outside of the melon, a green tint indicates a slightly under ripe fruit. A good cantaloupe should feel heavy for its size, and the blossom end should yield oh so slightly when pressed. Lastly, you should smell the stem end. If it smells sweet and musky, then you have picked a winner!