1.  Have dogs meet for the first time outside of the home, on neutral territory, so as to avoid any territoriality or spatial “comfort bubble” issues.  If you can’t meet in a truly neutral space, like a park, going for a walk up and down your street together can still do the trick. 

Begin with some distance and let the dogs see and smell each other without getting right up in each other’s space.  This may look a bit messy at first, as they may be pulling to try to get to one another, but if you just keep walking they will soon settle in.  Praise your dog highly if he moves forward or checks in with you rather than trying to pull to or lunge at the other dog.  And as they continue to walk and do well, you can gradually decrease distance.  See my article Introducing Fido to Rufus: Dog-to-Dog Greetings, Pressure Free! for more tips on executing this.

Multiple dog caveat: it’s more difficult and intimidating for a single dog to integrate into a multiple dog situation, since dogs that typically live together can develop a “pack” and are already comfortable with one another and the hierarchy they have set.  Bringing a new dog into this situation can stir things up.  So when introducing one dog to a multiple of dogs, it is best to do the introductions each individually at first (starting with the most laid-back dog in the multiple-dog group and working your way up to the most “intense” dog of the group).  This will give each dog the chance to get to know one another a bit without the “strength in numbers” tactics.  If each of the individual greetings goes OK, you can start adding one more dog at a time to the situation as all dogs are comfortable.** (see body language signals to watch for below)