"Do you mortify; do you make it your daily work; be always at it whilst you live; cease not a day from this work; be killing sin or it will be killing you. Your being dead with Christ virtually, your being quickened with him, will not excuse you from this work."
Nothing better has ever been written on the subject of putting sin to death in the Believer. At least that I have found. You can download various selections or find links to the whole book here.