My first (formal) job interview is next week, how should I prepare?

I've been looking at sample questions and trying to get a little story for all of them. I'm not really sure what else to do though.

What should I bring? I've heard to bring some kind of bag/ briefcase to keep copies of my resume or write stuff down in.

Just general tips really. Thanks!

EDIT: It's for a electrical engineer internship at a power company.