
Why is the first scene important? Well, because if the editor doesn't
like it, she'll stop reading. :)
Beyond that, the first scene should do a lot for the reader. It
should both establish the current situation and set up the need for
change. It should be intriguing, drawing the reader in and giving her
reason to keep reading. It should give a hint of the coming conflicts,
and maybe a starting point for the theme. It should introduce the main
character and the setting in a way that both explains and entices-- that
is, you want to give just enough information that the reader is intrigued
but not confused.
But too often, first scenes are either jammed full of so many details the
reader gives up.... or generic, like a dozen other opening scenes she's
read.