Are you sometimes stuck in those pentatonic boxes? Don`t know how to connect them and move up and down the neck? Why not try legato slides? The most important thing is to carefully execute the slides. Practise them very slowly until you become very comfortable playing them fast.
An exercise I developed recently for the left hand, a drill for the little finger, pinky (hammer-on till the dawn). It can be practiced on all levels (beginner, intermediate and advanced) depending on the speed.