Battery life is sacred for the mobile user, and despite steady improvements to battery technology (have you seen the urine battery?), the average user is still likely to find themselves in search of a convenient outlet at an inconvenient time. There are a few different ways to potentially improve your smartphone's run time, however, aiding in those moments you forget to bring along your portable battery charger.
Disable What You're Not Using
Through the normal course of they day, you likely enable your phone's various wireless features -- WiFi for the home network, Bluetooth for your headphones, NFC at one point or another. This is fine when you have your phone plugged in, but when you're out and about, you likely have no need for these functions, and they remain enabled only to suck your battery dry. Disabling these features is as easy as swiping open Settings and flipping the little blue switches, and will return precious minutes to your run time.
Use Power Saving Modes
Your phone likely includes a power saving mode of some sort, with some higher-end handsets including fairly sophisticated options for conserving battery life. Even if your phone only has a single on/off mode for saving power, however, it is still worth it to enable the feature and reap whatever boosts in run time it offers.
Battery Conservation Apps
If your handset's included power save mode isn't quite up to the task, a trot into the Play Store will reveal numerous app options offering better control of how your phone operations. Easy Battery Saver is one example, providing different modes depending on your needs, as well as the ability to manually customize how it functions if none of the modes are to your liking. Another solid option is Clean Master, which helps prevent apps from hogging your system's memory, and has the added benefit of removing unneeded junk from your system.
If you're feeling particularly desperate for longer run times and tweaks aren't boosting your time between charges long enough, consider going with a higher-capacity third-party battery (assuming your phone's battery is accessible). These batteries allow for a longer run time than the stock battery, and in some cases are large enough that they come with an extended backing to facilitate the increase in size.
If your smartphone's battery isn't accessible, there's still likely an option for you, namely in the form of a phone case that has an integrated battery. The PowerSkin for the iPhone is one example (check out our review), but many varieties exist for a multitude of handsets.