Military Press

Also known as Overhead Press, Plant your feet slightly wider than your hips for stability. Take the bar to the top of your shoulders. Press the weight up and over your head. Don't lock your arms at the top, keep moving, slow and controlled. In this variation, you're taking the bar to the front of your head, then to the back, to bring in different parts of the shoulder.
Bear in mind, you're also using your core and lower body to stabilise. Standing with your feet wider apart or together will also affect the need for stability. Take this into account when you choose the amount of weight you use.