Train them to heel at a young age and reinforce the command consistently and routinely. Dog is smart and will understand that certain behaviors are in its interest but only if it receives that message from you with uniform consistency. This is particularly the case for negative reinforcement; positive reinforcement can be less immediately effective but it does not have to be as ruthless on your part to work at all. Once listening to your “no” becomes optional, any behavior becomes similarly optional. When it comes to making sure it’s friendly with other dogs: some dogs are just conflict-prone and should be kept from approaching strange dogs: this is done by simply never allowing it to stray more than a set distance from you (easier trained the younger the animal). If it likes other dogs and isn’t aggressive with them you can train it to not run after other dogs by allowing it friendly contact with dogs but only within the allowable distance. This training should be on a leash; once the dog understands what is allowable and what is not you can start having him off lease.