One of the most effective techniques I have used to attain a more glute driven squat is to start with a progression:
1.) Just the bar, iso hold in the bottom position of the squat,15-30 seconds, focus on activating the glutes by sitting back into the hips, "pulling" down with the hip flexors, pushing out to the sides of the shoes, tightening the core, "pulling" with the feet, etc. You can mess around with many of these techniques until you feel the glutes turn on and take the brunt of the load.
2.) Decend into the bottom of the squat, pause at the bottom (5-10 secs), focus on attaining the same position as you achieved in step 1, and drive back up using the glutes to drive the lift.
3.) Progress into a standard concentric/eccentric squat, be sure to hit the same position in the bottom that you have been practicing in steps 1 and 2.
4.) (if applicable) Reactive squat- drop down into the same positon using the same cues, rebound out.
With more advanced athletes, simply using the pause squats (step 2) during the warm up sets, focusing on the extra glute activity, may be all thats needed to get a more glute driven squat.