Medicines

Put anything you have to take daily, as well as things like contact lenses and glasses, in your hand luggage. Keep prescription medicines in the original containers; the Transportation Security Administration (TSA) requires you to have proof that they’re yours.

Sleepwear

Chances are, your pajamas are one of the things you’ll need first, so put one set in the top layer. Keep the rest at the bottom, filling in the indentations caused by the suitcase handle.

Outerwear

Bring an oversize jacket or parka and bulk up with long-sleeve T-shirts, sweaters, and scarves. Packing a light jacket and several layers is more space-efficient than packing a heavy coat. Place your jacket toward the bottom of the bag. Better yet, wear it to save space. Store gloves in the coat pockets.

Pants

These should go at the very bottom of the suitcase, just above the layer that fills the three indentations made by the suitcase pulley (that layer can consist of underwear, workout clothes, and pajamas). For the first pair, place the waistband against a narrow end of the suitcase and drape the legs over the opposite edge. Position the next pair’s waistband so that it touches the opposite short end of the suitcase. Continue alternating with all the pants, then put all the other items — such as dresses, shirts, sweaters, and jackets — on top. Fold the pant legs over the pile of clothing. Packing experts call this interfolding. It helps prevent trouser creases.

“Good packing is really just about adding some learned behaviors to your natural preferences,” says McAlpin.