There are many steps the Catholic church took to convert people to the faith. There are three main ways.
First, the Catholic church has their charities. They believe that word and deed must go together. So, when the Catholic church goes out to help people through acts of mercy and charity, these people will most likely convert to Christianity.
Second, Catholics systematically have sent missionaries around the world. For example, John of Monte Corvino was a Franciscan sent to China to become prelate of Peking in around 1307. Catholics continued on other continents as well. The history of missions is amazing.
Third, Catholics have also been bastions of learning. Arguably the monasteries of the Catholic church were the first universities of the the Western world. Also today there are many Catholic schools that do a great job in reaching people. Some of the best universities in America are Catholic - Notre Dame, Georgetown, and Fordham. This educational commitment also can be seen in secondary schools.