Is davening permitted in front of a mirror?

One should not daven in front of pictures or paintings. These images can disturb a person’s concentration. If disturbances arise, one should close his eyes when davening. Davening in front of a mirror is forbidden even if a person closes his eyes, since it gives the impression that one is bowing to his own reflection. A person should also be careful not to daven in front of a window at night, since the contrast between the indoor light and the night sky accentuates his reflection. Some shuls place a mirrored plaque with various pesukim engraved on it in front of the chazon. The poskim permit its placement since it is not designated as a mirror for reflection.

סימן צ' סכ"ג ס"ק ע"א ביאורים ומוספים דרשו 82

Why is it forbidden to daven behind a rebbi?

A person may not daven next to, or in front of, his rebbi. It would be haughty to stand as an equal to the rebbi and certainly to stand in front of him. It is also forbidden to daven behind one’s rebbi. There are three reasons offered for this last halacha: 1) Davening in such close proximity to the rebbi is also haughty behavior. 2) When the student bows, it appears as if he is bowing to the rebbi. 3) If the rebbi finishes Shemoneh Esrei before the talmid, he will have to wait to take three steps back until the student finishes Shemoneh Esrei. This can be bothersome for the rebbi. Regarding these halochos, a rebbi is someone who taught the student most of his Torah or a gadol hador. Similar halachos apply to davening near one’s father.

סימן צ' סכ"ד ס"ק ע"ג-ע"ה

May a student daven near his rebbi in shul?

If a student and his rebbi are davening in a shul in their assigned seats, the poskim say that the concerns regarding the appearance of haughtiness or of bowing to the rebbi do not apply. Onlookers understand that these are their allotted seats and there are no sinister motives involved. Nonetheless, a student should still be careful not to daven behind his rebbi for the third reason quoted above (i.e. to avoid a bothersome situation for the rebbi). Some are stringent and avoid davening in front of a rebbi even in shul. If a student is davening four or more amos away from his rebbi, there are no restrictions. Based on the third reason, one who is behind his rebbi should stand four amos plus three steps away, so that the rebbi will be able to take three steps back without entering the four amos of the student. A talmid who is also a colleague has no restrictions regarding davening near his rebbi.

סכ"ד-סכ"ה ס"ק ע"ו-פ ביה"ל ד"ה ואע"פ

• When davening at home, one should pick a specific area where he will not be disturbed for davening.

• The Gemara says that a person should proceed “the distance of two doorways” into shul before davening. The Rishonim offer several explanations for this Gemara.

• It is best for one to daven facing a wall without any obstructions.

• Why do some people not wear a gartel?

• May one greet a bareheaded person by saying Shalom?

• May one daven while wearing a Purim costume?