Forget "hand strength", nothing about the guitar has anything to do with strength. Guitar technique is about finesse, muscle memory, and playing without tension. Make sure you are practicing at ridiculously slow speeds consciously being aware to how everything in your upper body is reacting to the movements you are making. Specifically making sure you are doing these motions totally relaxed....ZERO TENSION.
Edit: Now if you need help understanding the motions your hands, shoulders and everything should be making.....then that is a different topic altogether.