Starting from a stop is a must, not something you want to rush to get done- I flex my toes up, keeps me from cheating and you can def tell its burning the *** :o)

I feel as though if you focus on keeping your hips back and back straight, the weight in yours, with you toes slightly lifted you will get a better glute activation. Of course you also should keep you foot in the center on what ever it is you are stepping up onto and making sure you knee doesn't pass your toes.