Everyone goes through trying to house break their dog, whether it's a new puppy or a rescue, more than likely the dog will need a little training or reminder. When your dog is eliminating in the house, the best idea is to start over at the first step.
Setting your dog up for success1.
Don't give him the chance to fail. When your dog is eliminating in the house, most likely he tried to tell you in some way that he had to go, whether you understood it or not. Take your dog out at regular intervals.
Puppies cannot be expected to hold it in for longer than an hour per month old they are! (For example, a 2 month old puppy can only hold it in for 2 hours.) This means that you may have to take your dog out as often as every hour for a puppy. For any dog, take him out as often as he needs so that he can be successful.
2.
Know when he's got to go! Feed your dog at regular times. Whether you want to eventually free feed or not, regular/scheduled feedings should be used during house training. This means that your dog is going to need to go at about the same time everyday. Being able to predict when your dog has to eliminate is a great way to make sure you are there for her and setting her up to succeed.
3.
Potty Training and Crates. The crate can be a useful tool when you are unable to watch your dog, for example, when you are out of the house or sleeping. However, you need to make sure the crate is setting him up for success too. The crate should only be big enough for your dog to walk in standing, turn around, and lie down. A normal dog will not defecate where he sleeps, thus he will be very reluctant to have an accident. However, if the crate is too big, it might give him enough room to go in one corner and lie down in another. You want to avoid this. For a puppy, they make crates with an adjustable wall panel to change the size of the crate according to your dog's needs as he grows. These are especially useful for help in potty training.
Going outside4.
Knowing your dog's signs. Know what your dog looks like, his habits, his facial expressions and actions when he has to go. Koda will come right up and stare me in the face and then start licking my arm if he has to go to the bathroom. Know your dog's signs so you can listen to him when he tells you. If you're having trouble understanding your dog, a good idea is to put a bell on the door you use to go out to the yard. Everytime you take your dog outside, take his paw and swat the bell so it chimes. If you are consistent, eventually your dog will learn that ringing the bell means "I'm going outside!"
5.
Success gets PRAISE! THROW A PARTY when your dog is successful. You may feel stupid, but when your dog goes outside, praise, praise praise! Jump around with him, give him a little bit of play time, and lots of hugs and kisses. You want to reward that positive behavior.
Accidents Happen6.
Only correct the action, never the result. As tough as it sounds, you CANNOT punish the dog for a behavior that you did not catch with your own eyes. Dogs have no sense of cause/effect after the fact. If you don't see your dog messing in the house, he's never going to understand later what you're yelling at him for and you will just confuse him. (PLEASE DO NOT rub your dog's face in his mess... this will ONLY cause fear, aggression and mistrust. Your dog does NOT understand what that means.)
7.
Correct and Redirect. If you DO catch your dog in the act, issue a firm and sharp "NO!" Then IMMEDIATELY take your dog outside. STAY outside until he goes again. When he does.... THROW A PARTY. Lots of praise, loves and hugs. You want to show him that in the house equals anger, but outside means party time

8.
Make sure you clean up properly! If you do not use a cleaner that breaks down the urinary enzymes, your dog will smell where he went and think it is still okay to go there. That is why cleaning up properly is so important! Use an enzyme cleaner like Nature's Miracle. You can find it at any local pet store (even the large chains). You want to clean the spot THOROUGHLY so to avoid setting your dog up for failure in the future.
Extreme Measures9.
The tether system. Unfortunately, some dogs are just harder to train than others. In these cases where the above is not working, sometimes you might need to use the tether system. When your dog is in the house with you, attach him to your belt with a short leash. This way the dog is in your sight at all times. Keep your schedule and taking him out at regular intervals, but pay attention. The idea is that you're able to correct the bad behavior AS IT IS HAPPENING now instead of potentially missing it later. When you cannot keep the dog tethered to you, put him in his crate with a treat.
Again, the idea behind potty training is to set your dog up for success! If you are consistent, your dog will eventually understand. Patience and persistence are the key!