Originally Posted by AnubisXy

To make it "sound cool" you gotta play in key. Which means either using notes directly related to the chords (arpeggiation) being played in the rhythm, OR, using a scale with a corresponding root to the key that the progression is being played in. Ideally you'll arpeggiate the chords being played, most of the time you'll even be ok if you use just the pentatonic scales. As far as tapping, experiment, try different patterns, try string skipping. Move the patterns to as many different keys as you can, remember the intervals will stay the same, so you just need to shift positions. The Em pentatonic is special because it is made up of the notes of the open strings. It's a great place to start, interval structure is 1,b3,4,5,b7, notes are E, G, A, B, D. Have fun