The key to successful house training is supervision. Watch your dog constantly. Your first duty is to identify what your dog does right before it eliminates.
Some dogs provide signals that are easy to spot, while others are more difficult.
Lead the way, continuing to praise all the way. Once outside, stay with him until you witness the desired results and praise him as he goes. Make him feel that he is the most special dog in the whole world. By confining him to a small place, like an airline kennel, you will teach him to wait to be let out. He will be more reluctant to soil his crate, because if he does he will be forced to sit and look at it and smell it until you return.