Are you crate training him? How consistent are you with rewarding him for going outside and correcting him when he goes inside? Is he neutered? Is he lifting his leg? Lifting the leg indicates marking, and not the same thing as just straight urinating. Simple urination is done out of need. Marking is done out of instinct (though urine comes out either way). If he's already marking, it may be 'habit' already, neutering would probably help. You can get a 'belly band' and keep it on him, that'd probasby stop the marking.
To me, the key to housetraining any dog is supervision. You MUST be able to catch the dog in the act of going in the wrong place. If he is doing it when you aren't home, or doing it when you are in the kitchen washing dishes and you aren't watching him, he doesn't have enough supervision.
The crate training uses a denning instinct that is present in nearly all dogs. Dogs from pet stores and puppy mills are the exception to this rule, as they are trained practically from birth that it is acceptable to soil the 'den', or crate they are being kept in, which directly opposes the natural instinct of a dog that tells it not to go in the place where it eats and sleeps. Keep the dog in the crate when you aren't home (and it must be the smallest crate available for such a small dog) and as soon as you get home, pick him up and take him outside.
Get child gates and close off all bedrooms, bathrooms, etc. You want to keep the dog from getting out of your range of view. If the dog goes potty on the floor and you catch it in the act, say 'NO!' sharply in a way that lets the dog know it is doing something wrong, pick it up *immediately* (even if it is still going) and take it outside. Keep it outside on a leash, walking around constantly, until it goes potty again. Then give it praise and treats, and a little play time session. So it knows that pottying inside = bad, and pottying outside gets me treats and play time. Praise and reward the dog every single time it goes outside.
If the dog goes potty on the floor when your back is turned, and you turn around in time to see the wet spot and the dog has walked away, it's too late to teach your dog anything. Hit yourself on the head with a rolled up newspaper, clean up the spot with an enzymatic cleaner that will get rid of the smell like Natures Miracle (because dogs tend to go potty where theyv'e already gone in the past) and vow to keep a closer eye on the dog next time. If you miss seeing the dog going potty, it is not the dog's mistake, but YOURS because you weren't giving the dog close enough supervision.
If the dog keeps getting away from you to go potty, then put a leash on the dog and literally tie it to your belt, so you can be extra certain he doesn't get away from you.
Feed the dog at specific times, don'tleave food out for the dog, so you cna keep track of when he is eating, since the gastronemic reflex in dogs (and people) makes it so that they have to go to the restroom within about 15 minutes of eating. After every meal, take him outside. Take him outside after play time and after he sleeps as well, as those are also times when the dog will need to go potty.
If your dog is from a pet store or a pathetic breeder that kept the dogs in small crates through the early months of his life, then you need to invest in a small exercise pen to keep him in when no one is home, because he's probably going to potty in his crate. When you are home though, use the methods mentioned earlier.
***Edited By: Minniyar on 11/20/2007 5:06:38 PM*** Reason: add
Never trust a tall dwarf... he's lying about something.
I cant train my 4mnth-old peek-a-poo either! He goes outside and does nothing, and then as soon as he comes inside he pees on the welcome rug! we put a puppy training pad there but then you step in it when you walk in. ;^)~