Keeping him attatched to you is a great idea! Everyone has great suggestions, another to add is to give him a potty command when you are outside. I just use "go potty" and always reward him when he goes outside!

Another thing that should really really be done is to clean your carpets very very well w/ a product designed just for that purpose. If he catches his scent on the carpet he may think that because he smells it there than it is ok to continue to use that as a potty.