How to hold a guitar correctly for optimal playing technique?

To hold a guitar correctly for optimal playing technique, sit up straight with the guitar resting on your right leg (if you're right-handed) or left leg (if you're left-handed). Keep the guitar body close to your body and at a slight angle. Support the neck with your left hand and place your fingers on the fretboard for playing. Practice good posture and hand positioning to improve your playing technique.