By our living in the Spirit and walking after the Spirit. As we abound in the graces of the Spirit and walk according to them, the fruits of the Spirit restrict the fruits of the flesh, because the works of the flesh are contrary to the works of the Spirit. This renewing of us by the Holy Spirit, as it is called (Titus 3:5), is one great way of mortification. He cause us to grow, thrive, flourish, and abound in the graces which are contrary, opposite, and destructive to all the works of the flesh, and contrary to the thriving of indwelling sin itself.
*From The Mortification of Sin: Abridged and made easy to read by Richard Rushing, Banner of Truth, pg. 19.