How do you get your ensemble to practice more? Create trust.
I think that lack of practice is actually a leading indicator of insufficient trust. Building that trust will make it more likely that ensemble members practice.
Here’s why: a prime motivator for many student to practice is the trust that their ensemble fellows will be doing their own practice. If they don’t have confidence that anyone else will practice, they’ll be unlikely to practice.
Laying down the rationale and tool kit for effective practice is essential. But laying a foundation of member trust is just as essential.