Scales are the first thing that comes to mind when many think of technique. They are really useful and efficient for improving techniques because they combine many different demands of the guitar in one concise exercise. We can use them to focus on and improve aspects such as:
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Left hand placement and cleanliness -- that is, making sure each note sounds and avioding buzzes or muted strings
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Left hand position shifts -- three-octave scales that move all around the neck are great for this
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Tone -- producing a strong, round tone when we play, and learning to vary the tone for expressive reasons as classical guitar often demands
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Dynamics and expression -- even scales should sound like music!
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Articulation techniques -- such as ligados (hammer-ons and pull-offs) and playing staccato.
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Rhythm -- playing scales at various rhythms
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Velocity -- learning to play scales fast will help you with repertoire that demands velocity.
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Right-hand techniques -- alternate picking, free stroke and rest stroke in classical or flamenco guitar, learning to alternate right-hand fingers (index and middle), string-crossings
A few years ago I wrote this article that includes more information on scales and some exercises.
How do you practice scales? What other uses do they have that I forgot to mention? How have they helped you? How often do you play them? Can you recommend any particular resources or approaches?
