Overcrowding the Pan
Why it’s bad: Most of us pile chicken breasts into a skillet or heap oven fries onto a baking sheet if we’re in a hurry or we want fewer dishes to wash. But when a pan is stuffed, the heat that rises from the cooking surface becomes trapped under the food and creates steam, making oven fries limp and preventing chicken breasts from getting that delectable caramelized crust.
Do this instead: To help ingredients brown (which gives food flavor and locks in moisture), make sure the pieces aren’t touching one another in the pan. Patting damp food dry with a paper towel before cooking also helps. Don’t have a large enough skillet or baking sheet? Cook in batches, keeping the first batch warm on a plate tented with foil or in a low-temperature oven while you prepare the second. Or use two skillets or baking sheets (switch the position of the baking sheets in the oven halfway through the cooking time).