when working on large scores, the hide or show empty staves in the layout
menu can be very useful.  Let's say that you have a section you're working
on where there are bits of every orchestral section with some notes in them
but not every staff in each group has music.  Select a bar in that section
that has all the instruments you want shown and choose hide empty staves.

Now, and here's the fun part, as you go along and discover that you need one
more staff that was previously hidden, using the show empty staves command
will yield a list of all your choices.  simply select one more staff, and it
is added to the staves you see on screen.  This dramatically lessens the
amount of vertical moving you have to do in your large score to write what
you need.  I'm sure some of you already knew this and some others have no
use for it.  But I thought it was a cool thing.
Kevin