To break this habit, you will have to get up very early one morning (when you have plenty of time), and get your puppy out on a walk before it has had its morning wee. You should not bring it home until it has been forced to go out of desperation. If however, you are unsuccessful, and your puppy has not toileted, then take it immediately into the garden on your return, or you risk it relieving itself indoors. Need more help? Follow these additional puppy training tips (e.g. socialisation techniques to prevent behavioural problems) or visit the Puppy Socialisation Plan website.
Remember that training is an ongoing process. You will never be completely finished. It is important to keep working on obedience training throughout the life of your dog. People who learn a language at a young age but stop speaking that language may forget much of it as they grow older. The same goes for your dog: use it or lose it. Running through even the most basic tricks and commands will help them stay fresh in your dog's mind. Plus, it's a great way to spend time with your dog.
It’s best not to punish the puppy for making a mistake. Instead, focus on praising appropriate bathroom behavior. If you catch your puppy in the act, interrupt it by saying “No!” in a firm voice or clapping your hands loudly, then take the puppy outside to finish going to the bathroom. Never swat your puppy, yell at it, or try to rub its nose in the mess.