Augustus did a number of things to help the Roman Empire succeed.
First, he took power over the empire as a whole after the civil war that followed the assassination of Julius Caesar.
Second, he did some things to expand the empire. He finalized the conquest of Spain. He set up client kingdoms in the east of the empire so that the Roman army itself would not have to defend such a large area. He instituted reforms in the army that helped make it stronger.
Finally, Augustus put forward changes in society that helped to keep Rome stable. Most importantly, Augustus brought back an emphasis on religion. He felt that religion would help to bind the people together and keep the empire more stable. Therefore, he restored old religious rituals and buildings and also created a new imperial cult. These helped to make the empire more stable.