Remove the glass pane from the empty picture frame. Set aside the cardboard backing. Spray the both sides of the glass with glass cleaner. Wipe the pane free of any fingerprints or other marks. Hold the glass under a light or out in the sun to make sure it is free of any marks so the paint will coat evenly.
Spread the newspaper on a table in a well ventilated area. Shake the spray paint can for 30 seconds or until well shaken. Lay the pane of glass on the newspaper with the back side up. Spray a thin, even first coat, then let dry for 30 minutes. When the paint is dry, spray a second coat on and let dry another 30 minutes. If the paint is not black enough, apply a third layer.
Set the pane of glass back into the original frame once the paint is dry, facing the painted side of the glass to the back of the frame. Reattach the cardboard backing, securing the glass into place. Hold the black mirror in a light or sunlight, checking the glass for any fingerprints. Wipe any off with a bit of glass cleaner and a paper towel.
Set the mirror up on a table or altar space. Set the incense burner and an incense cone or stick before the mirror. Arrange any candles or deity statues around the mirror as desired. As you light the incense and candles, ask the spirits' guidance to see into the mirror.
Pull up a chair once all the candles and incense are lit. Sit straight up in your seat and take a deep breath, holding it for a few seconds. As you exhale, concentrate on what you'd like to see in the mirror. Stare into the mirror, continuing to meditate upon the premonition you wish to see in the mirror.
Continue to stare deep within the mirror for as long as you can. Do not give up if after 5 minutes you have yet to see anything. Practice scrying into the mirror for up to 30 minutes a day, each day concentrating on the same premonition you wish to see in the mirror until it is finally revealed.