The first thing we did was decide to Crate Train as a method of housebreaking and reducing the number of inside accidents.
The idea is that if the dog spends most of his time in his crate and is taking outside immediately after getting out of his crate, he'll learn to relieve himself outside and associate outside with where you eliminate.
This works because dogs instinctually won't mess in their own den and it will take a while for him to think of the whole house as his den, but will get the crate immediately, given the crate is not too large for him.
The crate also becomes a safe place for him to sleep at night. Safe for him as well as for our furniture!
Lastly, he will have a place to retreat to if things scare or startle him.