Adjust screen brightness. More is your screen brightness more your iPhone consumes power. So adjust your screen brightness to the lower level where you can easily see your screen without any problem. This will help you to make battery last longer.Or otherwise you can use auto brightness option in iPhone because it automatically adjust brightness according to the surrounding.But I personally think it’s better to use first option that I tell you.urn off your iPhone screen instantly after using. Turning-off screen immediately after using your iPhone or iPad can save a lot of your battery power. And believe me it’s very simple to do it.