Iphone 4 constantly needs charging - it there anything I can do?

I have turned brightness down. Is there anything else in settings that I can change to help it stay charged longer?

I had this issue for my iPhone 5. Cellular data on KILLS your battery. Location services off can save you some time. Turn Wi-Fi off when you're not using it. It is constantly looking for internet unless you turn it off completely. See if that helps! Let me know!