It is important to manage your time when practicing the guitar. Although players like Steve Vai recommend a 12-15 hour a day practice schedule: (http://www.picksnlicks.com/Guitar%20Lessons/Exercises/30_hr_workout/30_hr_workout_1.html). Most of us frankly don’t have that amount of time to dedicate to playing (at least not in any given week). In order to maximise the benefit for each practice session I recommend targeting the below four aspects of guitar. I’m going to use the example of an hour long practice session and highlight the type of practice you should be doing throughout.