Comfort is key when you're spending time on the slopes, and comfort starts with the proper clothing. It's a lot easier and more fun to concentrate on the skills you're trying to learn if you're warm and dry while you're doing it.
Dress in layers, and start with an inner layer of wicking materials (fabrics that move sweat away from the skin). Long sleeve tops and full length undergarments made of Capilene, polypropylene or merino wool will keep warmth in and moisture away when you're on the slopes.
Choose ski socks made from wool or other wicking materials. Avoid bulky socks in favor of thinner socks that won't bunch up in your boots.
Your outer layers should also be breathable, lightweight and non-restrictive. It pays to buy a jacket that's designed for skiing, it'll provide the freedom of movement you need, and have handy pockets, clips and vents. These little details will make your time more enjoyable.
Ski pants or bibs are a must. As a beginner you may spend a lot of time sitting in the snow, and proper ski pants will keep you dry. They'll also be designed to fit over your boots and allow plenty of freedom of motion.
Skis and Poles
Many experts recommend that you rent your skis when you first start skiing. Not only will you avoid a big investment in gear, but you'll be better able to find what length and type of ski is best for you. But if you're determined to get your own gear right away, here are some tips.
Shop for skis at a good ski shop and tell the sales person your exact skiing level. It's best to start with shorter skis as a beginner, since they're easier to control. As you gain more experience, you can graduate to longer (and faster skis). A good local shop will know the right kind of ski to use in your area, too. A ski built for floating on Utah powder isn't going to be of much use on an icy run in Pennsylvania.
Poles are pretty straight forward for a beginner--a simple aluminum pole of the right length for your body is fine--no need to spring for adjustable carbon fiber poles when you're getting started.
One quick note--avoid the $10 skis you saw at the yard sale. Newer "shaped" skis make cutting turns a lot easier than old-fashioned straight skis.
A good boot fit can make all the difference, both in control and comfort. Even as a beginner, an investment in good boots is wise one, since they can serve you well for years. To ensure a good fit, work with a good local ski shop.
Helmet and Goggles
Don't hit the slopes without your lid. A helmet not only protects you from your mistakes, it protects you from the mistakes of others, which is important when you're sharing the slopes with potentially out-of-control newbies. Pick a helmet that fits properly and is comfortable as well.
Goggles or glasses will let you concentrate on seeing what's ahead clearly, especially in poor lighting conditions. Spend the extra cash to get goggles or sunglasses with changeable lenses that you can switch for different lighting conditions.