The Tibetan Mastiff is known to be an intelligent dog, but their training has to be consistent right from the word go. They do boast a bit of a stubborn streak in them and will show a more dominant side to their nature if they are not correctly handled and trained when they are young.
It's also essential for puppies to be well socialised from a young age which means introducing them to new people, situations and other animals as soon as they have been fully vaccinated for them to mature into well-rounded dogs.