Where should you place your point of focus such that you achieve the maximum DOF ?
If you focus on the part of your subject that is closest to you then you are effectively wasting some of your available DOF. You are wasting the field that extends from the point of focus back towards the camera.
You need to focus at some point into the subject so you can leverage the DoF near field as well as the DoF far field.
For any given subject distance, focal length, and aperture you can calculate (or look up in a table) the focus distance to achieve the maximum DOF. This point is called the hyperfocal distance.