Select Start > Settings > System > Power & battery > Screen and sleep. Set a shorter duration for an active display.
It doesn’t seem like much, but if you enable haptic feedback on your keyboard and then post a full 260 character tweet, that’s 260 times the vibration motor ran. Turn them both off if you can live without them or, at least, use them sparingly. The motor drains battery over the course of a full day.
The fewer pixels your phone has on, the less energy your display uses. Thus, using blacked out themes, wallpapers, and other elements allow portions of the screen to remain off at all times. OLED screens display black by shutting off individual pixels on the screen.
This is also the only battery saving trick that works on LCD screens.
Your screen is usually the top source of battery drain. However, the lower your screen brightness is, the less energy your screen uses.
Google is slowly closing the doors on Android when it comes to stuff like accessibility, developer tools, and the like.