One exercise that i have been doing that seems to help is to look at the stars at night. Because stars are sufficiently far away, your eyes adjust to an "infinite" focus -- essentially what you need for Photofocus. While looking at a star, just concentrate on how your muscles feel, what your gaze feels like, etc and then try to recreate that feeling later.
What also works well is to simply close your eye lids and relax your eyes. This also will set them in a "neutral" state. When you open your eyes, pay close attention to the muscles around them -- you will actually feel your eyes focusing. The trick is to try to suppress that urge when you are trying to enter Photofocus (this takes a LOT of practice).
