Standing vs. Sitting
The Ashkenaz custom is for the community to stand for all of the tekiot. The Sefardic custom is for the community to sit for the first 30 blasts. In fact, these blasts are called tekiot demeyushav (the sitting tekiot). According to all opinions, the community should stand while the brachot are being recited. The one blowing the Shofar must stand during the brachot and the blowing.
During Musaf
The Chassidic and Sefardic custom is to blow the Shofar during the silent Amidah.
When one has completed the blessings of Malchiyot, Zichronot, and Shofarot, they should wait at that point until the shofar is sounded. Those who have not completed these blessings should pause while the shofar is being sounded and then resume their prayers at the point at which they left off.
The custom of many Ashkenazim is not to blow during the silent Amidah.
It is customary in many communities that the one who blows the shofar during Musaf need not be the same person who blew the first 30 blasts.
In addition, although the Ba’al Tokei’a stands by the Bimah (table for the Torah reading) when blowing the first 30 blasts, he need not stand there when blowing during Musaf. Rather, he may blow from wherever he usually stands during the prayers.
When blowing during Musaf, there are various customs as to which notes to blow. Every community should follow its own custom.
The total number of blasts should equal at least 100.
If one is in the middle of the Amidah while the Shofar is being blown, one should stop and listen.
One who is praying Musaf without a Minyan should not interrupt to blow the Shofar. Nor should he ask someone else to blow for him so that he can hear them during his prayers.
After the repetition of Musaf, it is customary to blow an additional 30 Shofar blasts to confuse the Satan. One who came late and missed (some) of the other blasts should pay special attention at this time.
One may not blow extra Shofar blasts on Rosh Hashanah as it is similar to playing an instrument, but one need not stop a child who does so.
How to Blow the Shofar
The Shofar should be covered while the Ba’al Tokei’a (shofar blower) says the brachot and whenever he's not actually blowing the Shofar. This is to evoke the merit of the binding of Isaac who was kept hidden while Abraham built the altar.
One should blow from the right side of his mouth (if possible). This is because one’s left side is already protected by one’s Tefillin. A lefty should blow from the left side of his mouth.
The shofar blasts are kosher whether the sounds are “thick” or “thin.” All types of sound are acceptable.
