You can use feature phones for days if its battery is fully charged once, but that's not the case with smartphones. You may end up charging your smartphone more than once a day based on your usage, which can be annoying.
Most smartphones, especially the high-end ones, come with high capacity batteries but its specifications like big screen, high resolution display, powerful hardware etc drain the battery. Some handsets have battery saver feature, but most phones don't have the option. However, battery life of a device can be improved by up to 30 percent with these simple steps:
1) Make sure that you don't keep too many apps opened at a time, as it not only drains battery but also consumes the system memory. Closing unused apps can improve battery life.
2) Toning down the brightness level of your phone and turning off the auto brightness and colour enhancer features can help save your phone battery. The brighter the screen of your smartphone, the more battery it consumes.
3) Turn off WiFi, Bluetooth and GPS if not in use, as searching for connectivity consumes a lot of power.
4) You can improve battery life of your smartphone by turning off syncing feature. Syncing apps like Picasa, Google Plus, Facebook, emails, Linkedin etc can eat up battery.
5) 3D and graphic heavy games consume a lot of battery power. Avoid playing such games and watching high resolution videos if you want your phone battery to last longer.
6) It is advisable to reduce your screen timeout or sleep time interval. Use auto lock feature to ensure that your phone screen is not turned on unintentionally.
If you still not satisfied with the battery life of your phone despite following the aforementioned steps, the only option left is to buy a power bank or a battery case.