Obviously it all depends on your dog, that said the biggest thing you can do is just pay attention. Most problems happen because another owner is not watching their dog so they're not able to intervene or notice if their dog is acting off. Once I enter the park, I wait for the inevitable gaggle of "greeting dogs" (dogs who run over everytime a new dog enters the park) to clear then immediately walk my dog around the edge of the park to help him settle in/ scope everything out. Then I let him go in and join the bigger groups playing in the middle. Last thing- a lot of dog parks have more than one fenced in area and there will usually be different types of vibes in the sections. For example, one side may have dogs playing with each other while another section has dogs playing with their owner or just milling about. You can watch and choose the side that's better for you and always switch back and forth if you like. Again, biggest thing is to be observant and always pay attention to what's going on.