1) 1) When the blower of the shofar makes the blessings for the blowing, the congregation should listen very carefully and intend to fulfil their own duty to make these blessings by listening to him. One should not interrupt these blessings by saying “Baruch hu uvaruch shemo” (as when listening to a blessing which one does not need to make). Rather, one should respond with “Amen”. From this blessing and onwards, one may not interrupt the prayers with speech until the end of the blowing in the Amidah of the additional service. (Kitzur Shulchan Aruch 129)
2) Some have the custom that after each of the sets of blowing from the shofar they say a “Yehi ratzon” which is printed in the prayer-book. Those who say this must make sure not to enunciate the names of the angels which are printed there. the main thing to do at the time of the blowing of the shofar is to repent wholeheartedly, as the Rambam writes about this point “Even though the blowing of the shofar on Rosh Hashanah is a Gezeras Hakasuv (biblical decree without reason given to human beings), it has an allusion. This means to say “Wake up, sleepy people, from your sleep, and slumbering ones, from your slumber and search your deeds and repent!””. (ibid)
