There are many ways a person can scry and into many different objects, but one I have read about recently is slightly different than normal and is more advanced than normal scrying. Wall scrying requires no mirrors or tools and therefore makes it a more readily available way to scry. It does however require you to have the knowledge of how to scry initially as it can be quite difficult to master, the rewards are definitely worth the hard work though.
As with all scrying sessions the first thing to do is set up your area by, making it as dark as possible and lighting a candle to give you just enough visibility to see. Find a bare wall, preferably south facing, place the candle behind you and stand facing the wall at arms length. Using your index and middle finger, draw and visualise a three foot in diameter circle in white, looking like it was drawn in chalk. Whilst still visualising this circle get comfortable and sit down ready to begin the actual scrying. The area within the white circle is going to act as your black mirror.
Get into a relaxed state, and if you know how open up your third eye through either meditation or your other chosen method, and begin to stare into the chosen scrying method as if you are trying to stare through it.Empty all of your thoughts or focus on the one thing your scrying about. Don’t strain your eyes while doing this just relax with your eyes open and begin to go into a trance or deep meditative state To do this stare at a spot on a wall with your eyes opened but relaxed. Let your thoughts drift away to nothing, and eventually you will see a sort of rain in front of your eyes. Switch to another point just off of where you were looking and you will be in the trance. focus back into the circle, clouds will begin to form and you will begin to scry.
At first it may take some time for the visions and clouds to appear as your vision has to adapt to the new size, this can take anything from days, weeks or even months to re develop. When they do appear you will notice that they appear to be slightly off of the wall and more close to three dimensions than normal scrying mirrors.
The first time I came across this ritual was in E A Koetting's - Works of Darkness and it instantly hooked me to try this for myself.