When dogs are properly socialized they are more confident and less stressed through their entire life.
Dogs are context thinkers and learners.  Which means, they learn as a matter of the result and/or situation.
 The best time to start exposing dogs to socialization is during the critical stage known as imprinting.  This is typically at the age of  eight to twelve weeks old.  However, it is important to always keep socializing your dog and doing this activity in different locations and situations.  Never stop socializing and exposing  your dog to new situations!
When exposing your dog to new situations keep it short, upbeat and give lots of high value treats.  Always keep your dog under control and safe.
Exposure to adults and children is a must.  However, timing and making it positive are important too.
Photos courtesy of David Speaker, Probizwriters (2016)
Here are just a few safe suggestions for locations to socialize:
Obedience classes, parks, events, parties, pet store and shopping centers.
Take your dog inside the bank on a leash well controlled, give some easy commands and leave.
Obedience classes referred by your veterinarian offer the best opportunity to insure success.
Have fun!  Remember positive repetition and consistency!  Be smart and safe!