This video shows some of the more common calming signals dogs display. Some of the video is from a Behavior Adjustment Training (BAT) session with a dog who is aggressive towards some other dogs, and the rest shows dogs at a dog park. Recognizing calming signals is essential for appropriate use of BAT, and helpful in many other pet-friendly training techniques as well.
For more information about BAT, you can peruse the information provided by Grisha Stewart (creator of BAT) here:
For information about BAT and other pet-friendly training for your pet, visit http://www.TheSophisticatedDog.com/ . A series of blog posts discussing BAT in layman's terms starts here: http://willmydoghateme.com/dog-training/training-tuesday-batboy-begins