Some things I've done to improve battery life on my N950:

Enable power saving.

Disable Dev Mode.Yes I've found this to make a big improvement. Also on N950 things like ssh is still active with dev mode disabled, once installed.

I've also disabled the standby screen under "Settings > Device > Screen > Sandby Screen". Don't know how much that power it saves, but I don't see a reason to have features enabled that isn't supported by the hardware.

Upgrade from 1200mAh til 1320mAh. Couldn't find 1400 mAh back then.