Freezer method: fill large ziplock bags with water, put them in the shoes/boots and freeze. The ice expands and stretches out the shoe a little. I've done this a few times and each try was successful.

will this work for Vans? DD has a pair that she cant stand to wear because they hurt.

I've only done this with leather sandals, not boots, so not sure if you want to do this, but wearing the shoes in the shower (not while you're actually showering, of course, just step in and get them soaking wet) helped speed up the break-in process for me. I had a pair of leather sandals that were giving me bad blisters but once I got them soaked and wore them that way for about 10 minutes, then took them off and let them dry, they felt great.

Is there a method to break in boots? In the past I wore them around the house, but was hoping for something quicker, like a spray or something that would be effective. Any success out there?