1 – Don’t allow any apps to run in the background unless they are absolutely necessary. Every running app put an extra load on your phone’s CPU and memory, and the harder the CPU and memory have to work the more power they consume.
While it’s true that Android suspends non-critical apps when they aren’t running front and center, many apps still use resources at all times for things like checking for updates or changes on a background server somewhere in the cloud.
The easiest way to hibernate unused apps is with the Greenify app.
2 – Unless you have a compelling reason for leaving it on, turn your phone’s GPS/Location services off since they are one of any phone’s biggest battery drainers.
3 – Disable Wi-Fi and Bluetooth when you aren’t using them. These are also major power sinkholes even when there’s no Wi-Fi connection in your immediate area or Bluetooth device in use.
4 – Decrease the brightness of the screen as much as possible while still being able to comfortably read it. At night (or when you’re in a dark room) you should be able to reduce the brightness by a huge margin and still read the info on the screen just fine.