P'sukei D'Zimra
Begin promptly whether or not there is a minyan or the room is
set up.
Mizmor Shir
L'Yom HaShabbat is repeated twice
in Siddur Sim Shalom; pick
only one.
If you are planning a lot of singing, or time is
short, or it is Rosh Hodesh and/or a long Torah reading, consider
omitting some of the Psalms, except for Ashrei.