you should have paid attention to your device's battery capacity. never the less here are some tips to decrease battery drainage
dont leave bluetooth or nfc on if you dont need it
use wallpapers with as much true black as possible
avoid live wallpapers
turn on dark mode as frequently as you can (if your device is running on android 9)
use always on display as less frequently as possible or set it to a schedule (if your device supports it)
use power saving as frequently as you can
there's a "reduce animations" toggle in your settings, turn it on (if your device runs on android 9 pie, if your device is on oreo you can turn the animations off from developer options)
turn off auto brightness (if your device supports it)
now, these are some things you can change to help your battery last longer, although it's perfectly fine if you dont want to sacrifice some of these things for more battery. just know that these are the options
