For Australian guitarist Orianthi Panagaris, pop smarts are as essential as precision fret-work. Her solo records serve up plenty of guitar acrobatics, yet they’re always in the service of a catchy song, like her 2009 breakout hit “According to You.” A similar dynamic informs her session work. While Orianthi’s shredding makes her popular with hard rockers, her rhythm playing for dance-pop stars like Jason Derulo reveals a superb sense of groove.