If something works then incorporate into a practice regime. If you try to run a marathon you won't get far unless you've already trained to run a marathon. Hydration is important but it's only a small part of the picture. If your muscles, tendons and ligaments aren't up to it you're not going to succeed and you'll be running the risk of straining or hurting yourself in some way.
As I said, practice, practice and practice some more. Use your hands in such a way as to train them up for speed and dexterity. Play lines faster than you need and then the slower speed of the song will make it easier to play.
Most of the time "Digging in" is wasted energy. Control your playing and increase your accuracy.
Then. . . . always warm up, relax, play softer, let the amp take the strain.