Guitar virtuoso Joe Satriani offered a very cool (but brief) guide on how to improvise on the guitar, stressing the importance of maintaining control over the jam.
He tells Guitar World: "When you play notes that are part of a chord - chords are made of notes, and those notes are suggestions. And those suggestions will make people in the audience think that you know what you're doing, if you reflect those suggestions."
'Once you step out, they're gonna say, 'Hold on, what are you doing?'. And then you've gotta take 'em somewhere, and you've gotta resolve it somehow. As long as you wrap it up, people will go, 'OK, I get it, you're just messing with me a little bit.'
"In the end, you're going back to chordal notes that are being presented by the band, the rhythm section around you."
He continued: "This idea of messing around with notes is really a jazz thing, it's not a rock 'n' roll thing. Rock 'n' roll's got a lot more rigid rules, because you're really focusing - maybe 50% of it - on the attitude."
Check out the clip below for his musical tips.