I'll be the first to admit, I know almost nothing about posing models/clients for portraits. It is definitely something I need to address, and it is one thing my TFCD shoots are helping me with. But I should probably find a model to help me to get more practice in.
Luckily, a great resource was referenced in this DPC thread. It is a PDF file of two models (one male, one female) in many, many poses, individually and together. I can't guarantee it will be around long, grab it or print it while you can (I have no idea of the source either). I'm probably going to print out the images on a few 8x10s (they aren't super-high res anyway) and bring them to shoots. Then, if I'm having difficulty describing a pose, I can point to the image and say: just put your body like this.
I also went ahead an did a little google research to find other posing information. There is a decent amount out there, but many are pay sites or books. Of the pay sites, the only one I would consider actually paying for was Photography Tips; they seemed to have a lot of good information.
The best resource of the bunch (if you are ok with photos from the 21st century) is The Zeltsman Approach to Traditional Classic Portraiture essentially a full book (with illustrations) covering everything from lens choice to posing guidelines (for children, women, men, and groups). I haven't read it all yet, but I will. While the book seems dated, I don't think posing is something that advances too much with time -- after all, human bodies are pretty much the same now as they were twenty years ago. Along those lines, Peter Gowland has a nice page about Posing Glamour with some really retro illustration photographs. But his tips seem pretty universal and he illustrates the ideas and principles well.
Obviously, much of my work will be with groups of people (families) so I found Posing Groups of People for Portraits to be very useful. Again, I haven't really studied it yet, but I will. And, while I'm not really interested in wedding photography in general, I'm sure most bridal portraiture principles can be adapted to other areas. There is a lot of info on the web, but I thought Monte Zucker's A Posing Guide for Formal Bridal Portraiture was the best of the bunch.
Finally, it always helps to look at posing from a model's point of view. Posing Tips For Models is a concise but information-filled web page that taught me a lot.
So, I'll leave you with two final posing tips by gi_joe05 in the DPC portrait 101 mentorship thread that really stuck with me:
General rules of thumb when it comes to posing:Needless to say, I have some studying (and practicing) to do. If you have any posing suggestions or resources I missed, leave me a comment!
1. If it can bend, bend it!
We are talking about wrists, elbows, and the like here. We are trying to avoid any straight line that we can.
2. NO STRAIGHT LINES!!!!
No really, straight lines are boring visually, slants and curves create movement. You want to move the body so that the shoulders and the head are tilted, wrists and elbows are bent, and that they are turned in regards to the lighting so that there is a shadow side and light side to the lighting on their face, thus creating direction and depth in your image.