By saving a fair amout of shots is how.
I guess you haven't been watching the games, or perhaps just don't know how to watch them to judge this guy. There were at least four or five soft goals in the Canada game and at least two or three soft goals against Swiss and Czechs.
He can't make up for all of them by making that one soccer goalie save against the Czechs since it was mostly a save because the Czech attacker simply was too slow to get his shot off.
I don't see an NHL team pick Sogaard in the first round after this. Even if he was the best goalie ever, he could not have won the game against Canada, but if he was a true first rounder he sure could make a handful of those pucks not go in.
His WHL-stats will get him drafted high if he keeps it up, no doubt, but not as a first rounder. These championships sent him down a couple of rounds.
But please also notice that not everyone agreed with the first rounder position in the first place. I personally only saw him on one list in top-31. Obviously I haven't seen every list in the world, but I did see some 6-7 other lists without Sogaard in the first round. Perhaps hockeyprospects.com is just not particularly good at this? According to their website they only have one guy covering the entire WHL for the NHL draft, so maybe it's just a guy looking at stats, not so much how good the players actually are? I don't know?
With this said and done I actually think he will do well in the relegation games against the Kazakhs. Then we will see what happens when he reverts to Medicine Hat.