1. Download Greenify
to stop apps constantly running bg.
2. Nexus 4 auto brightness seems to be very high. Indoor use 0% and outdoor use auto brightness.
3. Always charge your phone to 100% and dont recharge it until it reaches 5%-10%.
4. Switch your GPS to "Battery Saving" instead of High accuracy. To enable this mode, head to Settings > Location > Mode, and enable Battery Saving.
5. If you dont use Google Now disable it. If you use it sometime; just disable Hotword detection feature. Google Now > Settings > Voice, and disable Hotword Detection
6. NFC enable it when you only need it. Settings > Wireless & Networks – More > NFC. Disabling NFC will also disable Android Beam. Same goes for Bluetooth and LTE; enable it when you need it.
7. Stop autosync. With Kitkat google syncs everything purchases, Google Keep, music, books, contacts, and even photos. Each time you snap a picture, Google uploads it to your account to back it up. Go to settings and find your e-mail address under Accounts. Tap the account name again to access sync settings, where you can un-check the items you don't want synced. Included there is that "Google Photos" option. OR, head to the Gallery app > Settings, and disable Google Photos Sync. Now, if you have multiple accounts; make sure to disable it for each.
8. Do you really need live wallpaper? Disable it!
9. Avoid apps with lots of advertisements. Those ads are constantly refreshing, sucking up your precious battery life.