I found an interesting series of videos on how to shoot models. I figure it will transfer pretty well to shooting pics of people tied up too, which is what I am starting to do. If you are interested in getting better results when photographing your partner(s) then watch below. One note: audio quality sucks, but the info is very good.
One tip I have learned, use a long lens when shooting to replicate what the Pros do. Professional photographers often use a 200mm lens to give their lens a special look. While expensive, it does get great results. If you notice, the camera the photographer is using has an extra long lens.
Good luck,
MV
The House of Void 