High Brightness is the most known battery eater
Solution: Go to settings => Battery => Turn on Standby intelligent power saving and or battery saving mode. Do not set your brightness to auto brightness but set the brightness to 50% or 60%.
Background apps => This are apps running in background. In most case' android phone users do not properly exit when done using a certain app. So i suggest you download an app called "Task killer" from google play store.