While indoor elimination solutions like potty pads and litter boxes have their place, using them can actually slow the process down if you plan to eventually have your dog eliminate exclusively outside. Teaching your puppy to potty inside sometimes and outside others can be confusing because you will eventually have to teach your dog that at some point the indoor option is no longer allowed. Potty pads work best for people who can’t get their puppy outside quickly, like those who live in high-rise apartments or have limited mobility.
Just because your new dog is old enough that he should know where to potty doesn’t mean that he actually does. An adult dog has the necessary muscle control to hold it for longer periods of time, but if no one ever taught him the potty training rules then he’s the equivalent of a brand new puppy. Age should not be equated with housetraining prowess, so it’s a good idea to treat any dog new to your home as if he’s still learning the potty training ropes.
You may also notice common behavior problems in your dog such as jumping up, barking, or even aggression. The best way to correct any misbehavior is to interrupt it. Shift your dog's attention to something positive. Try running through cues that your dog has mastered followed by rewards. Keep your demeanor cool and confident, and be clear about what you mean.
I don't teach or recommend so-called "purely positive" methods that allow misbehaving pups to continue misbehaving, instead of teaching them which behaviors are and are not allowed. "Purely positive" is fine for teaching tricks and high-level competition exercises, but NOT for teaching the solid good behaviors that all family dogs need to know, and NOT for stopping behavior problems such as barking, jumping, chewing, nipping, chasing, etc.
Before you begin dog obedience training, choose the best method for you and your dog. Training styles vary, but most trainers agree that dogs respond best to positive reinforcement, such as praise or treats. One common training variation, known as clicker training, includes the use of conditioned reinforcer. There are plenty of dog training books and websites where you can learn about training techniques and determine which best suits you and your dog. When planning out your training methods, don't forget about socialization.

The process is the exactly same for older dogs as it is for puppies; prevent accidents from happening by using baby gates and a crate if possible, create a predictable schedule, learn to recognize your dog’s potty signals, accompany your dog outside and immediately reward for all outdoor elimination, properly clean any accidents and supervise your dog until you’re sure that he understands the rules.
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