An excellent way to improve your guitar technique is playing some of the compositions of Bach. Classical guitar has a different approach to guitar technique in comparison with jazz guitar and it's a good thing for every guitarist to play some classical guitar studies from time to time.
I arranged for you the presto part of Bach's sonata for solo violin no.1 in G minor (with tablature).
Play the composition with a pick and make sure every note sounds clear. If some positions don't work for you, try to find another way to play that certain passage.
Once you're familiar with the notes and positions, put some dynamics into the music. Try to speed up the overall tempo and put some accelerandos and rallentandos at the appropriate places.Recommended listening: "Essential Guitar: 33 Guitar Masterpieces"