How to hang a mezuzah: placement, height, angle and blessing

Roll the scroll from left to right so that the word "Shema" is visible first when unrolling and the name Shaddai, written on the back, faces outward toward the room. Wrap it in plastic film or wax paper to protect it from humidity, then slide it into the case.

Stand outside the room, facing the door, in the direction of entering: the mezuzah goes on the doorpost to your right, in the upper third of the post (measure the door height, divide by three: the base of the mezuzah sits at the start of the upper third). It must be within the depth of the doorway, on the outer side of the door, at least a handbreadth from the top.

Ashkenazim tilt the mezuzah, top toward the inside of the room (a compromise between Rashi and Rabbeinu Tam); Sephardim hang it upright.

Before fixing the first mezuzah, recite: בָּרוּךְ אַתָּה ה' אֱלֹהֵינוּ מֶלֶךְ הָעוֹלָם אֲשֶׁר קִדְּשָׁנוּ בְּמִצְוֹתָיו וְצִוָּנוּ לִקְבּוֹעַ מְזוּזָה. Then fix the case with screws or nails (double-sided tape is accepted by many authorities if it holds firmly). If you hang several mezuzot in succession, one blessing suffices.

In a purchased or rented home, the mezuzah must be hung upon moving in (in Israel) or within 30 days (in the diaspora, for a rental).