We've covered ton's of different types of banded glute activation drills here on our page. One of the most important things to consider when doing a monster walk is to PAUSE and MOVE SLOW. That brief bit of time on one leg should be used to drill home proper neuromuscular control in a single leg stance position, fighting the valgus moment placed on the knee by the bands. Far too often, people just aimlessly walk way too fast during the monster walk.
As with other banded exercises, make sure you KEEP CONSTANT OUTWARD TENSION on the band. Furthermore, make sure your BACK KNEE doesn't dive inward as you take a step with your other leg!