The indicator that a mind is set on the things of the Spirit, according to Romans 8:5-8, is to submit to “God’s law”. Here are the kinds of things Paul says:
Flesh-faced people are set on the flesh; Spirit-faced people are set on the Spirit (8:5).
Flesh-faced people move toward death; Spirit-faced people move toward life and peace (8:6).
Flesh-faced people are hostile to God (8:7).
Flesh-faced people do not submit to God’s Torah (8:7).
Flesh-faced people cannot please God (8:8).
“Flesh-faced” and “Spirit-faced” is my rendering of “setting the mind on.” Their mind and face and motion are oriented in that direction. As Wright points out, the thinking process here is more than just mental; it is the who orientation.
Death and life are an easy contrast for Paul; the addition of “peace” in 8:6 anticipates the chaos and hostility of 8:7-8.