There is a tradition from the Ba’al Shem Tov to recite three chapters of Tehillim each day of Elul. Ideally, these should be recited immediately after the Tehillim that is normally said at the end of Shacharis.
If one neglected to recite these chapters of Tehillim on the appropriate day, he should do so at the earliest opportunity.
Beginning on the first day of Rosh Chodesh, one wishes (both in person as well as in writing): “Kesivah V’Chasima Tovah L’Shana Tova U’Mesukah”. [The Rebbe included these wishes at the end of his letters. From Rosh Chodesh onwards, he would write only “Kesivah V’Chasima Tovah”, and would begin adding “L’Shana Tova U’Mesukah” from around the 18th of Elul onwards.]
Although the basic requirement is to check Mezuzuos and Tefillin twice every seven years, the Rebbe encouraged checking them every Elul (unless they were checked within the last 12 months). The Rebbe urged that this directive be publicized.
The Alter Rebbe’s Niggun known as the Daled Bavos, which is normally sung only on special occasions, may be sung during the entire month of Elul.
