How to improve your guitar playing when you have little time to practice.
Think about all the things that you have to practice in order to reach your musical goals. Some of things require that you have a guitar in your hand (such as practicing string bending) and other things will not (such as fretboard memorization).
You can learn, study, review or practice some things away from the guitar. When you do this you are able to spend 100% of your actual ‘guitar playing’ time on things that require you to physically play.
For example, let's say you need to improve in these areas:
Fretboard Memorization
Aural Skills (ear training)
Songwriting
Improvisation
Music Theory
Rhythm (timing)
Various Guitar Techniques