Wards for protecting spaces from malicious influences seem to be the most prolific sort of Magick. So I'll start by explaining a few kinds that I know of.
First is a Folk Christian ward to keep demons out of the home. I learned it as a child from an exorcist. (Mom wanted me to be one.)
The ward is simple. After long prayer and meditation, the person making the ward allows the holy spirit to enter into their body similar to a spirit medium. When they feel the power rising from the belly, they write "YHWH" in Hebrew on the lintel and posts of the doors of the house, or else anoint the doors with olive oil in the shape of a cross. My mother used to do this a lot.
In Okinawa, there is a practice of sacrificing a young bull in the spring and draining its blood. The blood is spread on the lintel and posts of the doors and windows of the home, as well as the corners of the house on the outside. Sakaki or other evergreen branches are used to spread the blood like a paintbrush. The entrails are hung from the village gates and the meat is cooked and eaten before midnight. It's supposed to keep the gods' wrath at bay and exclude evil forces from the village. (Not dissimilar to the Jewish festival of Pesah.)
In Shinto, there are Shimenawa and Torii. The Shimenawa is a sacred rope festooned with zig-zag paper streamers. They surround sacred spaces and objects that attract divinity to prevent impure essences from entering the space or sitting on the object. Torii is a gateway to separate sacred from mundane spaces. In the home, it works a little differently; There is a talisman made of paper or wood and inscribed with a blessing or protector deity and stamped with the seal of the Shinto Shrine that made it. It's called a "Gofu".
The Shinto practice is not dissimilar from the Jewish Mezuzah. http://en.wikipedia.org/wiki/Mezuzah