Im not expert but I do have a ton of experience with training my own pups. I took the time to add my training techniques on my web site. You can find them at
www.dawnsyorkies.weebly.com/training-tips
One little trick that I do it to take a poo poo that was left indoors and put it outside where you want your little one to go. Dogs are very scent oriented and will go when they smell their own or another dogs business.