Clothing for the Slopes
The proper clothing is even more vital to bring on a ski trip than equipment (you can always rent equipment). Remember to layer clothing items---temperatures and weather conditions can fluctuate wildly. Start by packing the outer, insulating layer of clothing first. Next add the middle layer and finish up with the outer layer that will be touching your skin. Don't forget items like gaiters, woolen socks, gloves, goggles and headgear.
Clothing for Off the Slope
Much of your ski vacation will likely be spent away from the slopes, so you'll need to pack clothing that's comfortable, protective and stylish to wear when you aren't actually skiing. Pack some sneakers and nice shoes in addition to your heavy boots. Bring along less bulky socks, sweaters and jackets to wear when you head out shopping. Pack a nice dress or dinner jacket to wear to an upscale restaurant. A pair of long johns is a good idea as well: You may need that extra level of protection even when you don't have ski poles in your hands.
If you haven't yet invested in a digital camera, pack slow-speed film for your film camera: Sun and snow can cause white-outs in your pictures if you use a regular-speed film. If you're bringing a digital camera, make sure your memory card has enough space to handle all the photos you'll want to take. Adjust the camera so that you give it a slight overexposure to make up for the brightness of the snow (how to adjust your camera for overexposure will depend on the specific camera you use, so consult the owner's manual). Also pack batteries: Digital cameras drain batteries quickly.
Health and Wellness Items
Extras that you should pack for your ski trip include sunscreen and lip balm to protect you from the elements. Don't leave home without your insurance information and a medical bracelet (if you need one), and print out a list of medications you're currently taking and any drugs to which you're allergic---keep these items on your body at all times. Accidents can happen very easily on a ski trip and you may not be able to communicate verbally if you're injured. Holding onto vital medical information that can be easily found and read could save your life.
If you've already purchased tickets or ski passes, don't leave these behind---keep them with your driver's license so that you don't leave home without them. You should also add credit cards, debit cards, traveler's checks, your checkbook and cash to this list of must-not-forget items.