Cinnamon uses a wizdog (
INDOOR DOG POTTY for: dog house training, housebreaking puppies, dog and puppy training), and I line it with puppy pads. It's great because the pee goes to the bottom so they do not have to walk on it. It's lightweight and easy to travel with. When I first got it when she was a puppy, I would put her on it every 20-30 mins, and tell her to go potty. I would bend her hind legs gently to get her to sit. Also, if I saw her sniffing around or about to squat, I would pick her up and run her to the wizdog and tell her to go potty. After she would pee or poo, I would jump up and down and say, "Good Girl! Good potty!!" She got the hang of it pretty quickly, but she had plenty of misses right in front of it every once and a while. I never got mad at her for accidents; I would only point to her wizdog and tell her, "Potty here. This is good potty."
I also trained her to get wiped after she pees so she doesn't get the little dribbles on sheets, clothing, skin, etc. After she pees, she scratches and scratches (like kicking dirt if outside) the floor until someone wipes her. We keep the wizdog upstairs in our bathroom, and if we're all downstairs, she'll run upstairs to potty/poo, then scratch at the top of the stairs until we come up to wipe her or pick up her poo to flush.