Just so you know, a puppy is never completely housetrained until they are 6 months old. For some breeds, even later. This means that though you may be making tremendous progress housetraining, there will be "mistakes". Sometimes for reasons you can't figure out! Don't fret about it. Stay focused on the progress you are making. Your confidence in the techniques you are using to house train your puppy will ensure your success.
One of the easiest ways to prevent accidents is learning to recognize when your puppy needs to go out. Most puppies will sniff the ground when they’re getting ready to potty, but there are many other more signals that happen prior to sniffing. Puppies that pace, seem distracted and walk away from play are subtly signaling that they have to go out. If your puppy tries to sneak out of the room, take a potty break right away.
Strictly following the model set out in the Koehler Method of Dog Training, some 50 years later, the Koehler method continues to be taught in both class and private training formats. The method is based in the philosophy that a dog acts on its right to choose its actions. Koehler explained that a dog's learned behavior is an act of choice based on its own learning experience. When those choices are influenced by the expectation of reward, the behavior will most likely be repeated, and when those choices are influenced by the anticipation of punishment, they will most likely cease. Once the dog has learned that its choices result in comfort or discomfort it can be taught to make the correct decisions. Action→Memory→Desire encapsulates the learning pattern used by the method; the dog acts, remembers the consequences, and forms the desire to repeat or avoid those consequences. Adherents believe that once the behavior has been correctly taught, it should be performed, thus making any correction, fair, reasonable, and expected. While the model has been used consistently since 1962, some of the punishment procedures described in the book are now not considered necessary, humane, or appropriate by many trainers.
Unless you plan to keep your dog outdoors--and few of us do because it's not recommended--you'll need to teach your dog where to eliminate. Therefore, house training (also called housebreaking or potty training) is one of the first things you need to work on with your dog. Crate training can be a very helpful part of the training process. This includes house training as well as many other areas of training: