This is a simple and effective exercise to work the top and the back of your shoulder.  It really focuses on your shoulder muscle and isolates it quite nicely.

To do it, you will need:

• A flat bench
• A dumbbell.

To do it:

• Lie on the bench on your side with your lower arm (the one touching the bench below you) extended to the floor to help keep your balance.
• Now grip the dumbbell with your other hand and extend it out at 90 degrees to your body in front of you with your palm facing downwards to the floor.  Then raise it up so that your arm is again at 90 degrees to your body but is now directly above you.  That’s one rep.  Continue to do about 10 reps for +-3 sets.  Make sure to keep your arms extended with a very slight bend in them throughout.  Don’t bend your arm too much as this will take the emphasis off the shoulder.

If you start to bend too much then the weight is probably too heavy for you.

You can vary the angle of your palms with this too see which feels better for you and which works more on the shoulder for you.  For instance you can start at the bottom of the movement with your palm facing towards your face and as you move it up you can start to rotate until the top of the movement where your palm will be facing away from you.  Or you can start with your palm facing away from you and keep it like that for the whole rep.