I have a suspicion I have dealt with this subject before, but review is always good!
It's important not to practice when you're playing. That would include things like:
- Shoehorning an idea or lick into someplace not because the music told you, but because your ego wants to justify the work you've done.
-Obsessing about micro issues like the placement of one's gear, rather than the sound and feel of the ensemble as a whole and making adjustments to the room you're playing in.
-Thinking about tunes and parts of tunes rather than concentrating on how these parts fit into the architecture of the set/evening of music.
Equally important is to not play when you're practicing. Elements of this would include:
- Playing things in the practice room you can already play.
-Play along to recordings in a non concentrating and inauthentic way. ( Practicing your double bass drum chops while playing along to The Stones, for example!)
-Not being focused, and not really hearing what you're playing. (E.g. Balance of instruments. Quality of sound on cymbals and drums etc.)
In conclusion, playing and practicing are 2 very important but completely different disciplines. If you confuse them, you will fail to get the benefit of either of them.