Originally Posted by: maggiorSo let's say I'm soloing in a song that a major pentatonic scale fits best in the key of G. I notice that this would use the same scale shapes as Em pentatonic. So I use those shapes and think "Em", but start on G rather than E to get my "center" and my ear takes me the rest of the way.

Not saying that is the best way (probably not actually), but it is A way.