If you follow these steps, it is expected that your battery will last at least 20% longer and your phone should be faster too.
To put things in perspective, if your battery lasts 5 hours, following these steps will make it last 6 hours or more.
Reduce the brightness of your smartphone's display
This sounds very simple, but it is so good for battery. Reducing the brightness is the great way to reduce battery usage. Plus, it may also slightly increase phone's performance.
Simply reduce the brightness of display to the lowest point where you still see things on screen.
Turn off Wi-Fi when not in use
This seems easy, but many people leave it on all the time, and that could drain the battery.
Turn off Bluetooth
If you are not using bluetooth, no point to have it on.
Turn off location
If you are not using location at all, there is no point in having it on all the time.
Close background apps
Allowing apps that dont serve any purpose to run in the backround will just drain the battery.
Airplane mode
Airplane mode might help reduce battery usage.
Uninstall unnecessary apps
See which apps you never use, and either uninstall or disable them.
Dont allow your phone to heat up
If your phone gets hot, it damages the battery.
Dont overcharge and dont let battery go low
When charging your phone, ideally you would charge it to 70%-80% and no further.
Also, you should not let battery go under 30%.
If you happen to follow some of these steps such as the brightness decrease, your smartphone will greatly increase in both performance and duration.