Start slow and use a metronome. Don't increase your speed or tempo until you can play through this exercise three times in a row perfectly without any mistakes. Then bump up the metronome's tempo by 10 beats per minute (BPM) and work on playing it three times perfectly again. Repeat this process until you reach a speed you want to end at.
Utilize your right hand fingers as economically as you can so you can play as smooth and legato as you can. Each finger should be using a free-stroke pluck. The last measure of this exercise has some fret hand movement from the 3rd fret to the open high E you will want to be aware of as well.