Potty training advice

I bought a pen for my chi. She likes to go in there when she's tired. I use it for when I have to leave the house. She never goes in the pen. Now, I am not having trouble house breaking her, it just takes forever for them to learn. This is what I am doing:
Un potty trained dogs cannot be left unattended when they are in the house. Puppies need to go, after they wake, eat or play. I take her out to the same spot everytime and tell her to go potty. When she does, I praise her and offer her a treat everytime. If she doen't go after a few minutes of waiting, take her back in, but put a leash on her. She should go wherever you arein the house. If you can't watch her, put her in her crate or pen. I found that when they are leashed in the house with you, there is no opportunity for her to sneak off and do her business. Also, if your dog is in her crate for several hours a day, she may not be able to hold it. Depends on the dog. I know my little girl can hold it for hours. Right now, she holds it all night. Allowing me to get some sleep. When I first got her, I was getting up with her 3 times a night. That was like having a new born baby again. A lot of work. Anyway, I know I will get her potty trained. I have done it before, but I was interested on techniques that may have worked for others. Please share!