make sure your boots are the RIGHT SIZE... they are probably to big... and get a foot bed from SuperFeet. Not SureFoot, SureFoot sucks... they don't contain the foot in a sub-talor-neutral position, they allow for excessive pronation, and don't keep the foot in the heel pocket like SuperFeet.
to make sure your boots are the right size, take out the liner, and put your foot inside the shell. Slide your toes up to the very front of the boot, cross your index and middle fingers and stick them down between your heel and the back of the shell. it should be a snug fit, if you can fit more than a finger and a half back there, your boots are too big.
Right Size boot+Superfoot trim to fit orthodic= happy feet when skiing. (landing backseat doesn't help either)
Superfeet Trim-To-Fit orthodic.
There is also a custom cork orthodic but it costs considerably more, and if you are still growing... a waste of money if your foot is gonna be bigger in 6 months.
But if you want the best fit, the custom cork is the way to go, make sure who ever makes it knows what the hell they are doing... because its easy to fuck it up if they don't. Ask them to explain Subtalor neutral position, pronation and supernation, if they look at you like you are speaking zulu, go somewhere else.
'Thats cause sidewalls are on the side of the ski' -justinm