Avoid immodest clothing. Dress and groom to show the Lord that you know how precious your body is.
You would not paint a temple with dark pictures or symbols or graffiti or even initials. Do not do so with your body.
Avoid habit-forming stimulants, tea, coffee, tobacco, liquor, and drugs.
Keep yourselves worthy. Stay away from those environments, the music, the films, the videos, … and the associations that draw you into immoral conduct.