What should I do if I see a coyote?

You can stop and watch, but do not approach it. As with any wild animal, if it feels threatened by someone coming toward it or chasing it, it may feel the need to protect itself. DO NOT FEED or attempt to feed them. Once a wild animal gets accustomed to being fed by humans there is much more likelihood that an individual will get bitten by an animal looking for food.
http://www.nps.gov/rocr/naturescience/coyotefaq.htm