"All ski boots (kids and adults) are now using 'Mondo sizing'. This is a universal sizing based on centimeters. The plastic outer shells are usually only in whole sizes, while the inner liners are in half sizes.”
"No need for thick (or multiple) socks - kids do better with one pair of thin socks. They should be snug enough to avoid wrinkles and tall enough to reach well above the height of the boot. You might need to reach in there a few times during the ski day and pull the socks up again. This smooths out the wrinkles and improves comfort. Stay away from cotton socks! Kids'll be warmer and drier with wool or synthetic socks."
"For small children, comfort is more important than high performance. Boots are the most important piece of gear, and a proper fit is essential to the whole experience. Too tight and they'll get cold feet, too loose and they won't be able to control their skis. These aren't Olympic racers, so no need to squeeze 'em into tight form-fitting boots."
"Skis come in all shapes and sizes. Alpine skis have a curved-up tip in the front, a waist in the middle, and a tail in the back. They are shaped a little bit like an hourglass. This is called 'side cut' and this shape helps the ski turn. The base of the ski is smooth, and when it's nicely waxed it will slide nice and easy. The edges of the ski are made of metal that can be sharpened so that it bites and carves the snow and the skier can turn and stop."