Tips: Setting one rack to the lower-middle position encourages concentration of the liquid released from the vegetables. This gives the meal more flavor.
Arranging heartier vegetables (potatoes) on the bottom and quicker-cooking vegetables (asparagus) on top ensures even cooking.
Make small folds to ensure the packets stay closed so they will contain the steam. If they fail to hold the steam, the fish and vegetables will not cook properly.
To check doneness, carefully open one packet at a seam and use a fork to check the fish--it should flake easily. Also use the fork to pierce the potatoes to make sure they're tender. Open the packets right after they come out of the oven to ensure the fish doesn't get overcooked.
4 1/2 lean protein, 1 starch, 1 vegetable