Before entering the Ohel, it is customary to write a letter to the Rebbe. Whether referring to one's own self or mentioning someone else's name in a letter, one should always include the name and mother's name (e.g., Isaac the son of Sarah). It is preferable to use one's Hebrew name. (It is customary that Gentiles use their father's name.)

Men should wear a kippah or a hat. Women should be modestly dressed, and married women should wear a head covering that covers their hair entirely (these are available in the welcome center).

It is customary not to wear leather shoes in the Ohel (slippers are available in the welcome center).

Candles may be lit on the designated shelves in the Ohel's ante-chamber (candles are available in the welcome center).

In The Ohel
There are separate entrances for men and women. Some have the custom to knock on the door before entering, as a sign of respect.
It is customary to verbally read one's letter (albeit quietly), then tear it up and place it in the enclosed area.

Customary prayers include the Ma'aneh Lashon and Psalms. Suggested chapters of Psalms include the Rebbe's chapter and the chapter corresponding to one's age (e.g., Chapter 31 for someone aged 30). There are Ma'aneh Lashons and books of Psalms in the Ohel's ante-chamber.

As a sign of respect, it is customary to exit the Ohel walking backwards.