It's gift giving time-- are there new skates in your future?
If you're an experienced skater, you already know the bad news-- new skates are awful, especially if you also have new blades; they just feel completely different. If you've been in rentals, you might even have the experience of suddenly not being able to stand up.
High level free style skaters have the fewest problems, for multiple reasons. First, their skill level is solid, so they have a more instinctive understanding of the balance and motion. Second, the new high-level boots are made of some space age material that allows you to skip the old, agonizing "break in" period, where the leather got soft and molded to your foot. (Unfortunately, it also means that these skates, which are essentially plastic, smell terrible after a while.)
For children and beginners, you're going to have an adjustment period. Here's some things to do:
Don't expect to go out and immediately skate exactly the way you did in your old boots, or the rentals. Some people feel an immediate comfort, or even improvement, but most people find it very disconcerting to wear new boots and blades. So the first couple of times, just skate around until you feel solid. Younger children especially, even if they are very good skaters, will be extremely sensitive to the change. Kids like things to be the Way They Are; they're the most hide-bound conservatives you'll ever meet.
Skate a lot
As you skate more in the new boots, your body will start to forget what the old skates felt like. You don't have to skate for a long time each outing, but come every day that you can for a couple of weeks.
Don't give in
Let yourself adjust. For beginners, trust me your blade isn't "mounted wrong" and it's sharp enough. The problem is with you, because you're still inexperienced enough to be very sensitive to changes in your skating environment. For parents, try to figure out the difference between actual pain and just that it feels different. Some kids fall a lot the first few times out. This can be for multiple reasons-- the blade might be a different length, which changes your balance; if you've switched from rentals, new boots will hold your ankles straight, which again affects the balance you've learned. Out-of-the-box blades from places like SportMart sometimes have a coating on the surface of the blade to protect it during shipping (we call this "factory edging". If you hear someone say, oh it's still got the factory edge, this is what they're talking about.) This needs to be ground off by a professional skate shop (do NOT use steel wool, although you can rub aluminum foil over it a few times.)
Listen to your child, but not too much
Ask "does it hurt enough for a bandaid?" or "do we need to stop skating now?" Most kids will answer very honestly to these specific questions. Sometimes even the ones who actually get off the ice, if you tell them okay let's go home, will decide that it's fine and get back on. Especially for a kid who loves to skate, telling them that "if the skates hurt that much, we'll just stop skating" will make them evaluate the discomfort honestly. I confess I have let kids get to actual tears before giving in on new skates, especially the ones that have established themselves as complainers. Seems cruel, but I haven't lost one yet. (You don't have to let your child cry, that's just me, meanest tot teacher on the planet.)
Make sure it's the correct size
The number one reason that kids can't skate in new skates is that people get skates that are too big. Do NOT, I beg you, get skates with grow room. One 1/2 size up is the biggest you can go. Extra socks or extra insoles are not the answer. Boots that are too big force a skater to tense up their feet to keep from slipping around inside (and doubled socks makes this worse). This is what causes foot cramps, which is extremely painful. Along with a boot that's too big, will be a blade that is too big. Blades are designed to have specific points of contact with the ice. If the blade is too long, that contact point will be in the wrong place relative to your foot, and it will be harder to stand up.
If you don't know much about skates, go to a professional skate shop
Even if it means a long drive, like several counties. Buy a known brand, like Reidel, Jackson, Graf, or SPTeri. Be honest with the clerk about your skating level (i.e. don't buy a freestyle boot for a beginner-- it'll be too stiff, and will have too big a toe pick).
Here are some prior posts on skates.