Here is a helpful article explaining how to improve the battery life on your iPhone and iPad.
I found two apps that were a drain on my iPhone battery because they were turned on all the time: My Radar Pro and Around Me. I didn't need them checking my location all the time so I set them to only check my location when I'm actually using the app. If you check you may find apps that are on all the time, and which you only need turned on when you are actually using the app.
Another feature mentioned in the article is Smart Invert Colors, which, when turned on, inverts the background color from white to black. Black uses less power. I tried this and didn't like the black background, so I turned white back on. I'll sacrifice a bit of battery drain to have a white background.
It's worthwhile to check your settings as mentioned in the article. This may help to improve the battery life of your iPhone or iPad.
Jim Hamm