What to do on Rosh Hashanah, in the order you need it: erev Rosh Hashanah (fasting, kevarim, mikvah), which greeting belongs to which week, the simanim and the bracha on each, how many shofar blasts a man and a woman must hear, Tashlich, and the shehechiyanu question on the second night.
Some fast Erev Rosh Hashanah. Some people have a minhag to fast on Erev Rosh Hashanah. No acceptance of the fast is required at Mincha beforehand — a person may choose to fast upon awakening.
OU guideMany nowadays do not fast; those who do often fast only until after chatzos. Some fast until close to the beginning of Rosh Hashanah, ending before Yom Tov begins.
OU guideOne who is fasting until after Mincha should say Aneinu in the Mincha Shmoneh Esrei.
OU guideWomen do not fast on Erev Rosh Hashanah, and children need not be educated to fast — it is not obligatory.
Going to kevarim. There are those who are noheg to go to Jewish cemeteries Erev Rosh Hashanah. The davening should be to Hashem in the zechus of the deceased, not to the deceased directly.
OU guideSome allow beseeching the deceased to be a meilitz yosher.
OU guideThe minhag is to give tzedaka after visiting kevarim.
OU guideOne for whom this is not the minhag should not begin doing so.
Mikvah Erev Rosh Hashanah. We are noheg that men go to the mikvah Erev Rosh Hashanah. For one who does not have this custom it is still worthwhile — there isn’t any halachic argument against it.
OU guideA father and son are prohibited from going together, including in the changing areas — not an issue of kibud av, but a matter of tznius, and the father cannot waive it. The exception is a son assisting an elderly or handicapped father. Brothers-in-law likewise.
OU guideThere is no requirement to educate a child in this (the purification is from a doubt of tumas keri), and young boys should not be brought to the mikvah.
OU guideRemove the shirt first and then the underpants, unless wearing a very long shirt that covers the mila.
OU guideOne who is unable to go should try to pour nine kabin of water upon himself. Some permit a steady stream (a shower); for Rosh Hashanah purposes one may be lenient, though not for other purposes such as taharas hameis.
Which foods, and how many. The meforshim and poskim also explain that we may create our own symbolic foods. There is no set number required and no obligation per se to eat any of these foods in particular — but the more the better.
OU practical summaryThe commonly eaten simanim include apple dipped in honey, beets, black-eyed peas, carrots, dates, a fish head, leeks and pomegranate.
A bracha on each, despite hamotzi. One must recite a bracha before eating the simanim, even though hamotzi has already been made. If both haetz and haadama are required, haetz should be recited first.
OU guideSince we are eating these foods mainly for symbolic purposes, we should make the bracha on a shivas haminim item first.
Challah in honey. Most people are noheg to dip challah in honey instead of salt. Eating challah dipped in honey is a universal custom, but is not halacha.
OU guideSome Acharonim say salt should still be on the table, because of lo tashbis melach.
OU guideBased on mystical sources, one should dip the challah in salt even if one dips it in honey.
Conduct is a siman too. Just as what we eat may have some sort of symbolic power, so too how we act and what we do can also have an impact on our new year.
Who is obligated. Biblically all men above bar mitzvah are obligated to hear the sound of the shofar. Chazal tell us that all women accepted tekias shofar upon themselves and are therefore also required to hear tekias shofar.
How many blasts. Men are required to hear at least 60 shofar blasts on Rosh Hashanah (lechatchila) — 30 before and 30 after Musaf. The minimum requirement (b’dieved) is 30 blasts each day. Women only need to hear 30 shofar blasts on each day.
No interruption once the brachos are said. Once the blessings have been said before (and for) blowing the shofar, no one in the congregation may speak or do any action that is a hefsek.
The tekios during Shmoneh Esrei. Although we blow the tekios during Shmoneh Esrei, whether or not one has heard or said the brachos doesn’t affect one’s fulfillment.
OU guideSome Acharonim (Pnei Yehoshua) maintain it does affect the optimum fulfillment, so it is best to try to listen to every word. If that interferes with one’s concentration, one need not worry about it.
OU guideWomen do not need to hear the tekios together with Shmoneh Esrei.
Who says the bracha when blowing for someone else. If a woman is fulfilling her obligation through someone who has already fulfilled his own, that person should not recite the bracha and the woman should. If a man is blowing for another male, the man may say the bracha; the individual fulfilling his obligation preferably should, and the toke’a should when he is helping an entire group.
A minhag, not a chiyuv. Tashlich is a minhag and not an obligation. While it is preferable to do Tashlich on Rosh Hashanah, one can also do so during the entire Aseres Yemei Teshuva.
OU practical summaryIdeally, say Tashlich on the afternoon of the first day of Rosh Hashanah — unless that is Shabbos. The minimum is the first paragraph, mi Eil kamocha.
Where. The preferred locale for Tashlich is a natural body of water — near a running natural stream or a lake, but not at a mikvah. There is an additional preference for a body of water with fish.
OU guideIn Yerushalayim the minhag is to say Tashlich at the communal wells, even though they have been sealed for many years.
OU guideOne who cannot easily make it to a body of water is recommended to say Tashlich wherever he happens to be. One who could not do so at water on Rosh Hashanah is recommended to say Tashlich on Rosh Hashanah anyway and then again during Aseres Yemei Teshuva, or until Hoshana Rabbah.
OU guideThe Vilna Gaon apparently did not go say Tashlich; it is unclear whether he avoided it entirely or only did not go to water.
Rosh Hashanah is a two-day Yom Tov everywhere, and both days are considered the same Yom Tov — yoma arichta — which raises the question of whether to make shehechiyanu in Kiddush on the second night.
The solutions. Wear a new garment (one worthy of a shehechiyanu, i.e. an important garment), or have a new fruit worthy of a shehechiyanu. If neither is available, shehechiyanu should be recited anyway.
OU practical summaryPlace a “new” fruit — over which you may say shehechiyanu — at the table for Kiddush on the second night.
A garment worn on the first day. If someone wore a new garment on the first day and didn’t make a shehechiyanu on it, they can then recite a shehechiyanu on it the second night, if they are still wearing it.
Which fruit. Contemporary poskim have pointed out that there may be an issue of making a shehechiyanu on a fruit that is available all year round, so it is advisable to find a more exotic fruit.
Baruch hamavdil. Saying “Baruch hamavdil bein kodesh l’chol” after dark at the end of Rosh Hashanah does not affect the additions in birkas hamazon, which should include ya’aleh v’yavo and “harachaman hu yechadeish aleinu es hashana hazos.”
Compiled from Rabbi Y. Dov Krakowski’s “Hilchos Uminhagei Rosh Hashanah” on the OU’s site (OU guide), and the “Halacha L’Maaseh on Rosh Hashana” summary the OU carries (OU practical summary). Nothing here is our own psak — every entry notes which guide it appears in and the sources that guide cites. For a personal shailah, ask your Rov.