If you're looking for a set of broad, round shoulders that really stand out, the Lateral raises is a great exercise for you.
The shoulder muscle consists of three heads, this is an isolation exercise that works the lateral head, also known as the side delts.
Use a weight you can manage. This is an isolation exercise, so it works best with low weight and high reps (between 10 to 15). Keeping a good form is very important, If you use too much weight, all you end up doing is swinging your upper body in an uncontrolled manner, which will take the pressure off your side delts, and will increase the risk of injury.
Don't allow the weights to touch your body at the bottom of the movement. Keeping the weight a little far from your body will keep the tension on your delts.
Lower the weight slowly. Don't just drop them by your sides, but lower them in a slow, controlled manner. Lowering them slowly will keep the tension on your delts, leading to more muscle growth. It will also prevent you from using momentum.
Don’t go beyond parallel when you’re raising the weights. This will engage your traps instead of the delts, and it puts unnecessary stress on your shoulders and might lead to injury.
Make sure to keep the arms almost straight throughout the movement. If they start to bend over its time to use a lighter weight.
Tilt the weight at the top of the movement. As your hands approach shoulder height, rotate your wrist so that your little fingers are above your thumbs. Turning the wrists at the top activates more muscle fibers.
Don't raise your wrists above your elbows. This will shift the tension off your side delts. Tilting the wrists might help to prevent that from happening.