I've got a couple.
A recent change in my thinking - Breaking the floor apart isn't a good cue. "screw the floor apart" or "dial the floor apart" works much better.
If you were looking down at your right foot in the beginning of a squat, think of gripping the floor and screwing/rotating your foot clockwise. Obviously, the left would be anti clock wise. And, your feet don't actually move, it's an intent. Rather than trying to just abduct the hip (break the floor), you're also trying to externally rotate the hip at the same time, if you screw apart rather than break apart.
If you do this just standing with no bar, grip the floor and dial it out, your glutes will be ready for war.
Also, consider playing around with your stance width and toeing out. Play with the toes-out first. Also, seems kinda obvious but it's kinda common - make sure your feet are symmetrical. A lot of people rotate one foot out more than the other. One of the issues with my own squat is I wasn't pointing my toes out enough. That one tweak has completely changed the lift. I thought I toed out more than I actually did.
Other than that, single leg deadlifts. Just because they fix or at least contribute to fixing pretty much everything....