Use the "Muscle Beach" Effect!

Whenever applicable use the muscle beach effect. Stick your chest out as far as you can like you are at the beach; this will not only put a small arch in your upper and lower back, but it will also make your spine more rigid. This, combined with abdominal bracing (tightening the abdominal and gluteal musculature as if you are about to be punched), will not only help prevent injury, but help you add weight to the bar as well.