Dog Parks

Dog parks are wild places when they're crowded. If your dog is extremely timid, small, fragile or shy I recommend you don't take him to a dog park for awhile. Socialize him with other dogs his size, take him to the petstore to meet on-leash dogs and enrole him in Puppy Classes. Bigger dogs do a lot better in dog parks in the beginning. There are written and unwritten rules in dog parks. I'll give you a list of the most important rules so that you can understand not only the kind of stuff that will happen (people will break the rules!) but you can obey them yourself:

Dog Park Rules

Your dog must be Spayed or Neutered. If you don't believe in spaying or neutering then don't take your dog to a dog park. Male unneutered dogs are extremely competitive, easily aroused, easily upset and obsessive. A female dog can be all of these things and will also bring it out in other dogs. If she is In Heat not only is she going to get her pregnant but there will be massive social problems all around the dog park.
Pick up after your dog. Just because your dog is allowed to roam free doesn't mean your dog is allowed to defecate wherever he wants. Appreciate that you and your dog aren't walking over piles of feces and keep the place clean.
You are responsible for your dog's behavior. Whether your dog is humping, bullying, hurting or scaring another dog you are responsible. For example if you have a large dog around one year of age your dog might find it extremely fun to push around the smaller younger dogs. If your dog is doing something like this you simply have to apologize to the owner of the other dog and put your dog on a leash. Keep an eye on your dog at all times.
Make sure your dog has had his Shots and Vaccinations. This is very important for the safety of every dog there and in particular your own. There are some really bad transmittable diseases and if your dog isn't up to date it's a risk.

Always be prepared with a baggy for when your dog does his business. Bring a leash just in case your dog gets into trouble. A dog park is actually a pretty rough and dangerous place so don't bring young children or plan a picnic. Generally the dogs that need to go to dog parks are bigger dogs and you will see a lot of them.

I highly encourage you to watch your dog carefully. If your dog is shy at first don't push him. If he can't handle a group of dogs charging in to come sniff him upon arrival don't bring him. If he's Aggressive don't bring him. If you are ever in a situation where you or your dog are extremely uncomfortable just leave. If all signs are good it should be a great opportunity for your dog to play, exercise, socialize and a great opportunity for you to talk to other dog owners.