A few tips that you may already know;
-Place a finger on the lock screen and turn the device to landscape for a shortcut to the camera.
-When viewing a text or contact and need to call that person just hold the phone up to your ear.
-PIP video viewing by tapping the box in the lower right corner of the video while playing.
-Swipe contact left to send a text, right to call.
That's my .02. Hopefully I'll have more to come.