You don't focus on any one thing. You become the act of awareness itself, without placing that awareness on any one thing. This is a powerful tool and heavily overlooked in western society. This is the heart of Zen practice initially. Soft focus is not daydreaming, as you are focusing on one idea to the exclusion of others when you daydream.
Soft focus begins with a relaxation of the mind and visual field.
You become aware of all that is around you simultaneously, but acutely aware that you are aware. This is Self watching Self. Pure observation of awareness itself. A bit of a paradox. Mediators can relate to this idea fairly quickly, as this is the purpose of many eastern meditations.