The night before:
Iron your clothes. The better they look before you leave the better they look when you arrive. Fresh ironing also allows clothes to lie flatter, taking up less room. Button all buttons and zip all zippers before you pack. Take a good look at your wardrobe to see if you can leave behind any repetitive or one-time- use items. Inexperienced travelers often take too much of what they don't really need. Experienced travelers take too much of what they do need.

Packing also means repacking.
Take your packing list with you. It can be your inventory list for re-packing at the end of your trip, making sure everything you brought makes the trip home as well.