To get the most life from your battery, choose settings that use less battery:
Connections: Turn off Bluetooth and GPS when you're not using them.
Wi‑Fi: Turn on Wi‑Fi when the phone is in a location with Wi‑Fi coverage.
Screen: Turn down screen brightness and set a shorter screen timeout.
Sync: If you don't need it, turn off automatic syncing for all accounts. This means you won't receive notifications when updates occur and you'll need to manually sync to get new emails.
Temporarily conserve battery power
Use Battery Saver mode to keep going on a low battery.
Also, avoid these battery-intensive activities until you can charge: