Re:Leaning back when pressing overhead?
i do the same if im not careful and my back thanks me for it in the morning with some aches and pains..
you want to use your abs to control the shape of your body along with your glutes. Get a firm grip on the ground with your shoes, tighten your glutes and tighten abs. try it a bit in mirror with no weight, then some light weight, it feels weird and strenuous at first but eventually it will come natural and mabye even give you a stronger platform from which to push from.