Production Questions

Before I send my web application to the big world, I just wanted to
make sure what kind of things I should change that I normally wouldn't
set-up in development mode. I know, for example, that I should set
the sessions key to something besides default, and to put some sort of
username/password (and utf-8 support) on the database via the yaml
file. Anything else (I'm making a school website, so hopefully,
apache and database stuff are already taken care of by the school)?

Does Model.find(params[:id]) still work, so long as I change the
capabilities in yaml file?

Also, for some reason, error_messages_for prints nothing in most of my
rhtml. I made sure the validations recognizes errors via save!, but
even with validations and the correct model name, errors still doesn't
give me anything. And I'm calling render. Any ideas what went wrong
with that?