Easily the most underrated part of goalkeeping is footwork. The very best goalkeepers in the world can move instinctively all over their box to always be in position for different shots and passes that come their way.
This drill requires the goalkeeper and a partner.
Place four cones in either in a box or rectangle pattern. You should be in the middle of the cones and your partner will stand outside of them.
Have your partner call out a cone number when he or she wants you to go.
Run to the cone, touch it, and get back to your starting position.
Repeat this drill 10 or more times. You can move the cones around in different shapes to create more of a challenge.