I always shuck my corn just before I want to cook it. Never buy pre-shucked corn as it loses it's freshness sitting there in plastic. I bring the water to a boil, but instead of salt like you would use for most vegetables, I use about a tablespoon of sugar. This helps to add sweetness to the corn. I put the corn in and boil at a medium rolling boil for about 8 minutes. The corn changes colour to a deeper yellow just before this.