| experiment with different fingerings on your left hand.
Try playing with index finger on the I, and your ring finger barring the V and Octave notes.
Also try playing with index on the I, ring finger on the V and pinky on the Octave.
With both fingerings, get used to resting your fingers on the strings over the 5 and Octave before you sound the notes. This will help you press down more gently and smoothly, so it doesn't sound choppy.
After each note is done sounding, leave your finger gently muting the string, but not fretting it.
Practice doing it slow without other music playing. If you can get comfortable doing it slowly, muscle memory will take over at speed.
This kind of pattern is one of the most useful tools you will ever have in any style of music. | 
