A client recently suggested a blog post on off-leash dog park etiquette. She uses our local parks frequently and sometimes gets frustrated with other owners feeding her dog treats. I know my basic rules for dog parks, but I went in search of good information to add to my recommendations. What I found was perfect! The following two links are from the Association of Pet Dog Trainers. (This group is a professional organization of individual trainers who are committed to education, promote dog-friendly methods, and have an interest in furthering knowledge of positive training. I highly recommend to clients that trainers they use be members of APDT.)
First, a link of general dog park etiquette. http://www.apdt.com/petowners/park/etiquette.aspx
Also, a wonderful list of dog park body language.
You can also find other great resources on the APDT website, including more information on dog parks (such as the pros and cons), and also guides for choosing a dog and choosing a dog trainer. Check it out!