I would find a big window that lets in indirect light. That works very well for portraiture. If your subjects are willing to pose for you, then just play! My daughter does NOT like having her picture taken, and when she does consent to having a picture taken, it better happen right away.. no waiting to find a good lighting situation.LOL Getting a full straight on silhouette is nice. This is my daughter and I happy to get it! http://365project.org/m9f9l/365/2013-11-18
What's really funny is that my daughter poured over pinterest looking for maternity shot ideas, and then she doesn't get into having them actually taken!