My current shtick with organizing and focusing practice time is a series of 40 fixed etudes; each of which lasts three minutes. Each is a specific study of one device or fretboard mechanism.
With most of my more challenging etudes, it takes a couple of weeks to nail it down accurately, then it takes another to get it up to consistent speed. Then the fun begins: I slowly become aware of many unknown relationships both mechanically and musically. Subtle and unrecognized left and right-hand difficulties make themselves known. This is accomplished simply by playing them a few hundred times over as many days.
As soon as possible, I play an etude with my eyes closed. I want the "information" part of the task to be wholly internalized. I watch my neck "in my mind" instead. The brain is always processing peripheral visual information, so I turn it off entirely by closing my eyes.
When fully memorized, you begin to visualize the upcoming arp while you are still playing the current arp. This is key to smooth and effortless transitions. Over time you can visualize ahead for longer periods of time. Remember that as a temporal art, all of music is *transition*.
When this etude becomes fully absorbed you will find yourself switching into pieces of it in average daily improvisation. A "clear pathway opens up" and you can scamper sure-footed to a place you intend without awkward scrambling or guesswork.