MAKE A PLAN AND STICK TO IT!
Like an architect planning a building, so must you plan the contents of your suitcase by creating a list.
A packing list eliminates the panic of last-second packing, serves as a handy guide for repacking at the end of the trip, and can be beneficial in the unfortunate event of lost or stolen luggage.
When planning your wardrobe, consider the events you will participate in both day and night and write down a possible outfit for each activity. Crosscheck this list to determine if one piece can cover multiple occasions.
Pick clothes that coordinate well together, based around complimentary colors.
Check the weather forecast of the destination and plan accordingly. Also, be sure to know the local traditions, where a t-shirt for dinner could be a serious blunder, or bare shoulders may bar your entrance into such places as St. Peter's Basilica in Vatican City.
For almost all outdoor activities, take pieces that can be layered. Forget dress clothes for every occasion. The world at large has relaxed its dress code, showing almost universal leniency to tourists.
Dark colors, a black dress or blue jacket, will get you through most dinners and plays.
TO PACK OR NOT TO PACK? THAT IS THE QUESTION!
Now that the wardrobe is thoroughly planned, stick with it. When packing, lay out the items you intend to take and reexamine your list. If possible, weed out single-use items and extras.
Set aside the pieces you intend to bring and ensure that they are clean and ready to be packed. Contact your travel agent about the hotel's in-room amenities such as a hair dryer, an iron and board, soap, shampoo etc. so you'll know what to leave behind.
Jewelry; don't take what you don't want to lose, and leave behind the flashy pieces that could attract thieves. Keep makeup to a minimum to save space, and leave the perfume behind when scented lotions will work just as well.
When it comes to the question of toiletries, travel kits are always the answer. Having a travel kit perpetually stocked in a waterproof case will save in packing time before the trip and aggravation after arrival.
Most personal toiletry items come in inexpensive travel sizes, so purchase these when- ever you see them so as not to arrive with a half-empty bottle of your favorite hair gel. And don't fill bottles up to the very top, for pressure inside the plane may force the contents to expand and overflow.