First, consult the weather forecast for your destination. Only sunshine during your trip? Leave the raingear at home — one secret to packing light is to only bring what you need, without adding "what ifs" to the bag.
Next, check with your accommodations to see what in-room amenities and toiletries they offer. Hairdryers and irons are standard at most properties, so need to pack them (and if they don't have them, leave items that need to be ironed at home).
Remember the 3-1-1 rule for carry on luggage (one, 1-quart bag with liquids no more than 3.4 ounces). Avail yourself of your lodging's toiletries when you can (many luxe spots even offer poolside suntan lotion). Do, however, throw in some individual Woolite packs or a small container of detergent so you can wash clothes on the go.
Now, before you put anything in a bag, make a list. Overpacking happens when you start grabbing drawers full of shirts and dropping them into your open bag (for a packing check list, see below). Write down every item you're going to bring on vacation.
Stick to a color scheme. A neutral background — think black, white, tan — with a few colorful accessories, such as a scarf or a sweater, will help limit what you're packing.
Wear your heaviest items on the plane. For example, if you're planning on hiking, wear your hiking boots on the way to your destination. For casual trips, wear sneakers and layers, including whatever outerwear you're bringing with you for cool evenings, such as a jacket or sweater. Basically, anything bulky that will take up a great deal of suitcase space should be worn (leave the sandals and shorts to pack in your bag).
Consult your list and lay out everything where you can see it. Do not add anything to this. The secret to traveling with a carry on bag is to not overstuff.
Roll it up. T-shirts and shorts should be rolled to both save space and cut down on wrinkling. Start with a shirt face down flat on a flat surface. Fold the arms back so you have a perfect square. Fold in half vertically. Now roll up from the bottom to the top — voila, a perfect cylinder.
Fold and go. Heavier materials, like khakis and sweaters, should be folded into squares.
Bag it. For lingerie and delicate items such as bathing suits, use mesh lingerie bags (you can find these at most drug stores), which will allow security to see your items without actually touching them and keep small items organized.
Dress up. For dresses, skirts, blouses or dress shirts, place each item on a hanger, and place in individual plastic drycleaner bags. This keeps clothes wrinkle-free (the plastic reduces friction) and organized.
NOW you're ready to pack your bag. Stack square shapes first, then rolled items around those. Tuck shoes and flip flops into corners (and remember that shoes don't need to travel next to each other). Socks can be placed into shoes, or into empty spaces. Place your toiletry bag on top of your perfectly folded clothes so you can reach it easily for separate screening. Then lay your plastic wrapped dress clothes on top and fold over to fit into the bag. Zip and go!
3 shorts or skirts
2 dressy options (mix and match with accessories and outerwear)
1 outerwear — sweater or jacket
1 pair sneakers
1 pair dressy shoes
1 pair flip-flops
2 bathing suits
1 cover up
1 athletic outfit
Accessories (scarves, jewelry)
Write everything down before you start packing
Lay out everything where you can see it
Do NOT add anything else to your suitcase once you have it packed