I so rarely use a pick anymore it's awkward when I try to use one. But when I do, I hold it with my thumb and index finger with the point not quite vertical but slightly pointing to the headstock. I anchor my hand on the bridge fo riffs and move it forward for solos so as to mute the other strings completely. But the most important thing is to find what's comfortablr for you. I've seen lots of different picking styles.