Work on your overhead squat today(OHS). The overhead squat is probably one of the most effective exercises for developing impecable squat form, shoulder flexibility and rock hard abdominals. This exercise, no doubt will give much bang for your buck!
Try to get 75 reps of OHS with a resonable weight. Break it up as needed. If you have not been doing this exercise I suggest you start with a piece of PVC or just the bar. Take a wide grip, push the shoulders up.