First and foremost, keep clients and work colleagues (especially management people) out of your personal life as much as possible.

Communicate to the rest of the team and clients (if in a client facing role) when you will and won't be available. Also communicate your concerns about any unrealistic deadlines.

Most of the times, this is bound to be ineffective. So, keep phone on silent (or flight mode) at night and during weekends. Also don't call back in case there is a missed call from anybody from work colleagues.

I deviate from this only if there is a go live or similar activity going on.