With the advent of simple software this technique is very useful and helps you take the best of the photo. So
For this Bokeh/ Blur effect you will have to use a camera and cannot be taken using a mobile. You may though use the cheat apps which blur some part of the picture but still getting the quality would be poor. While the other tip of one third still can be used using your mobile.
Ever wonder why some angled picture don’t look as apealing despite the fact the photograph is preferred when the face is not facing the camera directly. As a photo at an angle removes the flattening effect of the photograph