How to make iphone battery last as long as possible?

Going on a last minute camping trip tomorrow and as with all iphones the battery goes quick, well mine does anyway. Any tips to lengthen the battery life? Have a iphone 4s, Thanks

Switch off Wi-Fi as there will be no Wi-Fi connection, lower your phone brightness to zero, kill the background application which ever you uses the last. Check all unnecessary thing should be switched off if you really want to make iphone battery last long.

There are a few things that you can do like turning on aeroplane mode, this turns of Wi-Fi and Bluetooth because if you are not connected to a Wi-Fi network then your phone will constantly be looking for a network to join which will use up battery life. Another way to save battery is when your not using it, don't turn it off, just lock it. Because when you turn it back on that use's battery aswell. But the biggest killer for battery life is the brightness, ideally you want it about a third of the way full. No more than half way. Hope this helps!

Do you just want to keep it charged for emergencies or do you want to have it on? If you put it in airplane mode or even switch it off, it should last longer. If you do want to use it at all, turn down the brightness.