Advice on how not to lose your shirt with owner-paid utilities

[Caleb Webster]

For rentals where the landlord pays all utilities, what strategies do you guys use to incentivize lower utility usage from your tenants and reduce your overall utility bill? 

I've heard of thermostats that you can restrict to a predetermined range. Are those legal? What is the approx. ROI on low flow faucets and toilets?

Assume in this scenario that utility bill-back is not an option.