On Erev Rosh Hashanah, one should reflect and take stock of the entire year, making all necessary corrections and utilizing the opportunity for Teshuvah. It is a universal custom to immerse in a Mikvah on Erev Rosh Hashanah after midday.
Some including Chabad hold that one should utilize all his spare time on Erev Rosh Hashanah to be busy with Torah and Mitzvot and not to be distracted the whole day with Teshuva. Some including Chabad have the custom to recite Tehillim, especially from one hour before Mincha and onwards.
Some have the custom to buy a new knife on Erev Rosh Hashanah as a Segulah for Parnassah. Some however just sharpen their existing knives. It is customary to accept upon oneself a Hiddur Mitzvah. This should be done on Erev Rosh Hashanah, or on Rosh Hashanah. [One should state that his acceptance is Bli Neder.]
Just like on a regular Erev Shabbat, it is preferable to refrain from eating a proper meal once the tenth Halachic hour of the day begins (3:33pm), in order to properly enjoy the Shabbat and Rosh Hashanah meal at night. However, one may snack in small quantities.
Prior to candle-lighting, one should give Tzedakah for the two days of Chag. One should arrange a pre-existing flame with which to light the candles on the second night of Rosh Hashanah. Candle-lighting time is 5:59pm.
Most have the custom to say the Brachah, L’Hadlik Ner Shel Yom Tov, some, including Chabad say L’Hadlik Ner Shel Yom Hazikaron, all follow the Brachah with Shehecheyanu. If eating out, one should ensure that practical benefit is derived from the candles after Chag begins.
Since it is Chag, if one neglected to light at the proper time, one may – and should – light candles on Chag itself, from a pre-existing flame. When a man is required to light candles, he does not recite Shehecheyanu, as he will be doing so in Kiddush. Similarly, if a woman needs to recite her own Kiddush, she does not recite Shehecheyanu in Kiddush, as she already did so at candle-lighting.
Mincha is davened at greater length than usual, as it is the last Tefillah of the year.
