1. Location Services - only enable for the apps that should know your location (i.e Google maps, Transit apps). Disable this for Facebook at ALL COSTS. Prefer to set "Use while in app" unless "Always" is needed. In Location Services, go to system services and only enable: Compass Calibration (Google Maps won't show your direction accurately after a while or at all if you don't), Find my iPhone (if you use that) and Frequent Locations (for predictive traffic in maps/gmaps).
2. Background services - either disable completely (also disables geofencing) or enable only for the apps that you need to access background. Note: Skype will not show app badges with this disabled, but it will still show notifications. I alternate between disabled completely or enabled only for Skype and Dropbox (for auto camera sync on wifi). Everything else jives fine without it
3. Manual Brightness! - it stops the proximity sensor and ambient light sensor from polling constantly (this is the real reason why people blindly recommend this). Whatever brightness is comfortable to you. There's a trick where you can dim the screen via triple press home, even on stock iphone via some accessibility settings. Google it
4. Notifications - I see a lot of people leave these enabled for EVERYTHING. Be realistic. Enable for what you need. When you receive a notification, the screen turns on and takes up some battery.
5. Calibrate your battery once/week or every two weeks. Let the battery die, charge it to 100% and leave phone connected for another 45 mins. I can write an essay on this, please challenge me.
6. Don't clear multitasking!!! Don't close apps manually unless you absolutely have to. The CPU, Disk and RAM has to work harder to start an app then to retrieve it from cache. This can have a considerable impact on battery life. A lot of people developed this habit from the 128/256/512MB phones which choked when everything was open. It's not needed any more, the memory management is pretty decent now.
7. The following apps abuse VOIP permissions to do whatever they want in the background without your permission: Facebook + FB Messenger and Hangouts. Replace Facebook + Facebook Messenger with the official Facebook Paper app (might need to change your Apple Store region to US then back, it's SUPER easy). It's a much better app in terms of navigation, aesthetics, battery usage and allows messaging AND news feed in the same app.
8. Unless absolutely needed, disable vibration. That little motor uses some serious juice when your phone is getting hammered with notifications. Note: starting that little motor from 0RPM takes more battery than keeping it at constant RPM so use this to your advantage in your vibration pattern if you must leave it enabled.
9. DO NOT USE PUSH EMAIL unless ABSOLUTELY necessary. Set the refresh interval to 15mins/30mins or an hour. This is huge (that's what she said). This is the number two draining element behind Location Services but I'm too lazy to switch it
10. This is something I don't have a problem with but if you are in an area where the signal is bad, daily, your battery life can take a huge hit. If I was experiencing that I would leave it, but you could for example enable airplane mode or disable Cellular Data (no data, but u still get SMS+Calls) and/or disable LTE (3g is still hitting HSPA+ speeds, no worries there). Enabling Airplane mode before you get on the subway is not a bad idea. Personally I can't be bothered to baby my phone like that anymore.
