I came across this post, and while it's not specifically steampunk, I think it's still very applicable. Every steampunk wants to have cool pictures, but not every steampunk knows how to get them. A good photographer will help you pose, but not everyone has access to professional photographers. Since you can't rely on having posing advice during a shoot, you should familiarize yourself with some of the tips in this post.
Maybe someone on this site can write a steampunk-specific guide to posing!