"Open minded" and "closed minded" are terms that most of us can relate to and have experienced either in ourselves or others. A deeper level of mind is belief, and deeper still is will. If we don't have an "open will," we won't have an open mind or open beliefs.
Will is a commitment of being. In order to Awaken, we must be willing to commit to the Unknown (call it Presence, Love, Divine, or God). This is what is meant by an "open will," willing to commit to something greater than yourself. Most of use are limited by our willfulness, you know, "I want what I want and I don't want what I don't want." Even when Grace opens us to Love free from restraints, unconditional, most of us will stop at the door. Many might look through, but few are willing to enter into the surrender of Absolute Divine Love, into the Heart of God.
Those with an open will, those who are willing to surrender, open to a never ending Love, and a pure heart, and a pure vision. They enter into an unconditional, all encompassing, never ending, absolute Divine Love. It is a Love of Divine Mother and Divine Father that hold us safely within Their Hearts. It is a Love that brings fulfillment to all.
"I understood that love comprises all vocations – that love is everything, and because it is eternal, embraces all times and places." ~ St. Therese of Lisieux
So, if we have an open will, how do we begin? Begin where you are. You may be at the first stage of forming relationship with the Divine through prayer and/or meditation. You may be at the second stag of becoming aware of presence, the Watcher within. Sitting in Presence begins with a trickle of awareness of some Presence beyond our mind and emotions. The more we are "present to Presence" the deeper we become immersed within it.
You my be at the third stage where we become flooded, or overcome with Presence. When recognize Presence as God's Divine Loving Presence, we begin to move into the next stage. You may be at the fourth stage of absorption into Divine Union with the essence of Mother Father God - Absolute Divine Love. When this Divine Union takes place, all action becomes and expression of Divine Love.
Another way of saying all this is God first, God in self, and God in all others.