1) On Succos we recite Hallel while holding the Lulav and Esrog and at different points of Hallel they are shaken. The poskim discuss the proper procedure in the event that one does not have a Lulav and Esrog in Shul. Does he (a) recite Hallel with the minyan and without the Lulav and Esrog and only afterwards take the daled minim, or (b) is it better for him to wait and recite the Hallel later b’yichidus (without the minyan) with the Lulav and Esrog. Harav Shmuel Kamanetzky shlit”a (Kovetz Halachos Succos page 372) maintains that one should recite Hallel with the minyan without the Lulav and Esrog (option a). However, Harav Gavriel Zinner shlit”a (Netai Gavriel Succos page 334) disagrees and he writes that it is better to recite Hallel with the Lulav even if that means reciting it without a minyan (option b). [See, however, Netai Gavriel on Daled Minim where he seems to agree with Harav Shmuel]

2) There are differences between those that pray Nusach Ashkenaz and those that pray Nusach Sefard as to when to shake the Lulav and Esrog in Hallel. Harav Shmuel Kamanetzky shlit”a (ibid. page 368) maintains that if one is praying in a shul that differs from his personal Nusach it is preferable to shake the Lulav and Esrog in accordance with the shul’s custom (and not his own). However, he concedes that the common custom seems to be that each person shakes them according to his personal custom regardless what shul he is in.

1) On the first afternoon of Rosh Hashana, after Mincha, it is customary to recite the Tashlich prayer at a body of water, preferably one that contains living fish. (Rama 583:2)

2) If it will be too difficult to go after Mincha, one may go before Mincha. (Mateh Efraim 598:7 and Netai Gavriel Rosh Hashana 69:1)

3) Harav Ovadia Yosef zt”l (Chazon Ovadia Yomim Noraim) explains that the reason for this custom is based on the Midrash which states, “When Avraham Avinu went with Yitzchak to Mount Moriah to offer him as a sacrifice, the Satan preceded them on the way and began to persuade Avraham against this and prevent him from fulfilling Hashem’s commandment. When the Satan saw that he was unsuccessful in persuading Avraham against sacrificing Yitzchak, the Satan went before them and turned into a large river so that they would not be able to cross. Nevertheless, Avraham and Yitzchak continued on their journey and entered the water until it reached their necks. Avraham Avinu then lifted his eyes heavenwards and exclaimed: ‘Master of the World! You have appeared to me and told me, Take Yitzchak, your only son whom you love, go to the land of the Moriah, and bring him there as an offering. I have not thought twice about this and I have not hindered your command. If we drown in this river, who will sanctify your great name? Save me G-d, for the water have reached my very soul!’ Immediately, Hashem castigated the Satan and he disappeared.” The Zohar states that Akedas Yitzchakoccurred on Rosh Hashanah; it is for this reason that the Torah portion read on Rosh Hashanah deals with Akedat Yitzchak. Similarly, it is for this reason that we customarily go to river or pond on Rosh Hashanah in order to recite Tashlich on Rosh Hashanah in order to commemorate the merits of Avraham and Yitzchak.