Like alluded to previously, I don’t tend to frequent dog parks.  They can be incredibly unpredictable and somewhat risky; since neither of my dogs are particularly great dog-park dogs I largely avoid them.

It really isn’t the end of the world not frequenting dog parks.  There are other, and I would argue, better ways to socialize our canine companions.  Do you feel you would have learned your best, most appropriate social skills at a frat party?  My guess is that a frat-party type environment is probably not the best place to learn social skills… well not the best for well-adjusted people.
Since I don’t often utilize dog-parks I’ve had to find other ways of socializing my dogs (especially my poorly socialized Shayne).
Group Walks

I like to get together with multiple dogs (and their handlers) to go for nice leashed walks regularly (anywhere from 1 other to 8 other dogs).  Dogs do quite a bit of socializing just getting to hang out with one another on a walk.  They are smelling each other, exploring space together, learning how to be together as a larger group, learning how to read each others body language and social cues.  Since everyone is leashed and under control, these tend to be really positive experiences–which, for insecure dogs like Shayne, are absolutely crucial in re-socializing an adult dog.  If you can get a regular set of dogs on these walks (and the dogs fit well together), you can work towards off-leash walking and off-leash play.
Chill’n like a villain


Like people, dogs don’t have to be physically playing to be socializing with each other and learning how to exist with their own kind.  If other dogs aren’t resource/food guarders, I like to set up outdoor picnics/lunches with other people and dogs.  Dogs just sort of relax together while people eat and relax (or no eating if there’s a resource guarder).  A well socialized dog should know how to relax and hang out with other dogs, not just be crazy and play.
Make Specific Friends

When Shayne was at one of her more reactive stages, I spent time letting her get to know a small number of dogs one-on-one.  We started off walking together on-leash and then we moved to walking the dogs off-leash together and eventually going over to each others apartments to hangout inside.  Shayne really had to learn how to exist with another dog in a variety of places and got a crash course in learning how to be a dog–working one on one was extremely valuable.  This one-on-one work started with leashed walks and ended with dogs running, playing, and wrestling together–but because both dogs know each other so well and trusted each other, the play was really quite nice.
Take a Training class
Training classes provide a great opportunity for dogs to socialized in a controlled environment.  Dogs are looking at each other, smelling each other, and learning to work with other dogs near.  Some classes even have play-time where dogs can socialize in carefully selected small groups.  Since this is another very controlled experience, it is often another positive experience around other dogs for those reactive or fearful dogs.
Small Group Off-leash Play/Hikes

Once you have a few good doggie friends, made either through leashed walks together or one-on-one working, you can start having a small group of dogs interacting off-leash.  Through all the work done previously, you already have a group of dogs who have a relationship with one another.  You have also built-up many positive experiences through their prior interactions leading to the off-leash time…it’s like putting money in the bank.  Every good experience makes a deposit into an account and if there is a scuffle or an issue it’s like making a withdrawal.  Because you have had so many positive experiences, there is money available to take out with out depleting the account–basically, if there is a scuffle there is still positive experiences in the bank for the dogs to fall back on and continue to have a good relationship.

 
So, while dog-parks may seem like the only option to socialize dogs, there are many other ways to socialize dogs.  I would much rather set my dogs up for success by knowing the dogs are going to be good fits or that the owners are responsible enough to make sure all the dogs are safe.