Many international airlines have rules that require smaller carry-on luggage than U.S. airlines, whether those rules count by centimeters or kilograms. No matter what baggage regulations your next flight has, you can be ahead of the game with these packing solutions. They’re tried-and-true (by me, over decades of travel) and ensure that everything you need for a week-long trip will fit into even a 20-inch carry-on wheelie (plus a laptop-holding handbag).

• Wear your heaviest shoes. If you need to bring bulky footwear, wear it on your feet rather than taking up space in your luggage.

• Pack your oldest socks and underwear. You can discard them along the way, making room for souvenirs you pick up.

• Stick to just two or three colors of clothing, and avoid patterns and stripes. That way everything matches and can be worn with everything else. I usually pack mainly black, then add color with a bright silk scarf (in summer) or pashmina shawl (in winter).

• Opt for luggage with few compartments. This might sound counterintuitive in an era when we have to cram so much into such a small space, but in my experience, extra zippers, buckles, and straps just take up space. I’d rather have an empty box-like space so that I can use those precious extra millimeters to cram things in. I do like to have an outside pocket, though, so I can quickly reach items I’ll need to access, such as my ultra-light compressible parka and pashmina.

• Use zip-top bags of varying sizes to make space and stay organized. Instead of using a carry-on with lots of compartments, I make my own “compartments” with zip-top bags. They weigh nothing and take up no space. I place my liquid toiletries in one (for easy removal at airport security), my dry toiletries in another. I vacuum-pack clothes in a two-gallon-size one, and I create my own inflight amenities kit by throwing eye drops, ear plugs, eye shades, Vitamin C, etc. into a sandwich-size Ziploc.
• Carry travel-sized, multi-purpose toiletries. Use 3-ounce-and-under sizes of multi-purpose toiletries (e.g., facial moisturizer with SPF, shampoo-plus-conditioner that you can use as shaving cream) and liquid toiletries in disposable packets rather than bottles (e.g., makeup remover pads; hand-sanitizing wipes).

• Bring 3 or 4 plastic grocery bags too. Like Ziplocs, they weigh nothing and take up no space. I use them as shoe bags, and they can also hold laundry, protect a camera from rain, etc.

• Pack travel-size detergent. Use Woolite packets or Tide singles to wash clothing in your hotel-room sink.

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