1) Draw from the melody as part of your improvisation. This is a foolproof way to play something satisfying and stay respectful to the composition itself.
2) Don't look at the chord changes. This forces us to really listen to our bandmates and also the harmonic movement of the tune. Doing this reduces the likelihood of playing practiced lines.
3) Take a moment and pause. It takes great confidence not to play. When we allow a bit of space between phrases, everyone becomes engaged; the band, the audience, and the soloist.
4) Learn it… forget it… then do it. If we know something well enough where we can disengage the conscious mind and tap into the subconscious, we can then set the stage for deeper creativity.
5) Stay committed to a piece. It's ok to tire of a piece played too often. Force yourself to dig deeper and draw out fresh perspective. Familiar territory is not an impediment to creativity and spontaneity can be created through applying conscious effort.
Special thanks to the great bassist & composer Chuck Israels for his helpful and knowledgable input.