Before proceeding to change the settings to improve your battery life, check what is taking up more battery. You can check it by navigating to Settings> battery and here you will be able to see the list of apps sucking your battery.
Here is how you can save battery-
1.Reduce brightness- In any Android device, it is the screen that consumes more juice. Set the brightness to minimum you are comfortable with. You can do this by navigating to Settings>Display>Brightness. Set Auto Brightness to ON. Change the Auto-Sleep to less than 15 seconds.
2. Use Power saving Modes- The MiUI on Redmi 1S provides three different power saving modes. Go to Security app, navigate to Power. Now under Battery Configuration, you have the option of setting it up for Marathon, Default and Sleep modes. Set any of them to check how it saves your battery. You can also set sceduled Power saving modes. For instance, set it to run in Sleep mode at night hours.
3.Disable connectivity features - The Redmi 1S comes with slew of connectivity options. Disable the unwanted connectivity features like NFC, Bluetooth and GPS. You can enable them as and when needed. When you are in a non coverage area for prolonged hours, set it to the Airplane mode.
4.Using launchers - Some third party launchers are found to be effective in saving battery. Try some launchers like Google Now or Nova launcher.
5.Use dark wallpalers/themes - Make it a point to use a darker wallpaper. Most of the apps provide themes for the appearance. Use dark theme which will be helpful enough to save your battery.
Live....and Let Live!