The following information is what I use to protect and guard my
house against physical and non-physical harm. This means everything from theives to ghosts. I feel that what energy you project into the universe can come back to help or haunt you.
I believe that rituals anchor the energy that is used for protection, but that ritual itself is not wholly responsible for that energy. You can do magick without any ritual, but this is hard for many to do, so we these tools to help focus the mind and overcome the "rational" mind's inability to accept magick.
Various rituals or objects which are useful for visualization and focus can be gleaned either from books, others in the craft, or even personal experimentation. Here are some that I have found helpful: