How do I make anxious, nervous dogs feel better?

I agree that taking them on a long leashed walk together may help. I usually head right out the door with my dog and a client's dog for a leashed walk right after dropped off. I have found that it calms dogs immensely, even if it's just those initial dog meet dog play frenzies. ;) I have an awesome dog trainer that does "socialization" walks where she pairs people off in twos and they walk their dogs alongside each other. She says this can be one of the best ways to acclimate dogs who are experiencing social issues/anxiety with other dogs. I have also read and been told not to give too much attention/coddling to an anxious dog as this can reaffirm to them that their behavior is correct/good and something is wrong. So my advise would be,take a walk together and keep them separated as long as you feel a dog may react out of fear. It may help to give your dog a "break" in a crate or a separate room, depending on your dog/situation. This way the dog is not threatened, but also not having their anxiety reassured :) Good luck!