What is a good way to save battery on the Iphone5?

I'm going camping this weekend from Friday night to Sunday morning and I'm taking my IPhone 5. I want to watch a movie on it and save battery. Any good tips on saving energy?

Lower the brightness, close all apps, turn off Wi-Fi, maybe put it on airplane mode so no one can text you can slow down the connection

See the app BatterySense by Philips (it is free).In a more general sense, close down all apps you are not using. When you finish your movie, turn it off completely.