A mourner [during the first eleven months of mourning] does not lead the prayers on Rosh Chodesh, nor on any day which has a Mussaf service. This restriction applies even to Maariv and Minchah.1

On the eve of Rosh Chodesh [and so too at any other time] one does not interrupt one’s prayers to announce that the paragraph known as יעלה ויבא (Siddur, p. 113) is to be said in Shemoneh Esreh.2

In the paragraph of יעלה ויבא, the first בו is pronounced bo, whereas the second [likewise the third] בו is pronounced vo.3

It is customary4 for a person praying privately to recite the opening and concluding blessings of Hallel (pp. 241 and 245) even when the entire Hallel is not recited.5

The verse beginning הודו לה' (p. 243) is repeated after each of the next three verses, even when one is praying alone.281

In the concluding paragraph (p. 245), the word על should be omitted.281

The verse beginning ואברהם זקן and the following sentence (p. 245) are said three times.

All pairs of tefillin are worn before Mussaf, but the passages for daily study [such as Chitas] are deferred until after the conclusion of all the morning prayers.281

According to a time-honored custom, every Rosh Chodesh one studies one verse from the chapter of Tehillim that corresponds to his age, together with the commentary of Rashi (and, if one so chooses, other commentaries as well). [For example, a thirty-year-old studies Psalm 31.] If the Psalm comprises fewer than twelve verses, and so too during a leap year, one repeats this study in subsequent months in such a way that the verses will match the number of months in that year. If on the other hand the Psalm contains more than twelve verses, one studies several verses on each Rosh Chodesh.6