Your shoulder muscles are your deltoids. There are three of them: middle, posterior (back) and anterior (front).
Strong shoulder muscles help with any effort in which you push weight overhead, or to the side or front of the body.
Well-defined and bulky deltoids also help create that triangular shape that bodybuilders seek.
Here are my top targeted exercises for the shoulders..
For the raises, you can use both dumbbells and cables. Upright rows can be done with barbells and dumbbells.
See a more detailed guide to weight training practices and procedures here.