I assume you mean, how can you increase maximum duration your laptop will last on battery power.
Main power draws are generally gpu, cpu, screen and wireless (wifi/bluetooth).
So what can you do:
- 1st check you do not use some High performance power plan when you are running your laptop of battery.
If you made sure of it you can try some/all of these:
- if your battery is older it may not be able to keep high level of charge anymore. You can download software to show you battery wear level, for example HWMonitor. If you see that it's low you may think about buying new battery.
- screen - lower brightness to minimal level which is still comfortable for you
- gpu - if you got 2 gpus in your laptop (integrated and discrete) try to switch to integrated only.
- wireless - if you do not need wifi / bluetooth - turn it off
- disable various features/devices you do not need - camera, cd/dvd drive, backlight of keyboard. Ofc if you will want to use it you will have to enable it again.
- one of last resorts is to lower maximum CPU frequency/power state. This can also be done in power settings, but I shall warn you this can make your laptop slugish.