I am edging into improvisation (guitar), and wonder if any improvisors out there have any tips. For instance, Rick Fielding swears by (and occasionally at) the use of the major pentatonic scale as a fail-safe method for most improv (e.g. in the key of C: C, D, E, G, A, C, avoiding the 4th and 7th) where you can't really make anything sound too terrible. I would also be interested in how people envisage improvising: do you see the various lines that you and others are playing spread out visually, do you do it all by pure instinct, or occasionally have to go into chord structure theory as you play, junk around with the melody and hope for the best, or what?

yours, Peter T.