Buy quad skates with adjustable & rubber toe stops. Measure your skater's feet and compare them to the appropriate sizing chart(s). Each brand has their own sizing chart so be sure to refer to it for the correct size. Devaskation has a really great comprehensive page to help with this.

Skates should be snug but not cut off your circulation. Your should be able to wiggle your toes but your feet should not slide. Sliding = friction which causes blisters - Ouch!

If you have the correct size but are noticing some discomfort, try a different lace technique.