HAVE A PLAN
I once helped a friend pack, and was shocked to watch her put food and dishes and medicine and gardening supplies all in the same box. I asked why on earth she did this, and her response was, "That's just how I picked things up." Unfortunately, once she got to her new home, she ended up spending two days hiking all over the house to put things where they belonged.
If you will pack your treasures by room -- storing all of the items that belong in the bedroom in one box, those that will go in the bathroom in another, stuff for the kitchen in a third -- packing will go by twice as fast. And be sure to LABEL each box -- with both the room it belongs to and its contents ("books," "cookware," "towels," etc.).
Taking a few minutes to create a master inventory list of all your boxes and their contents, according to room, will also help you make sure nothing gets left behind in the move.