In the Catholic Church, that is
By Father James Martin
In the early church, men and women were named saints by public acclamation. The martyrs, those who died for the faith, were instantly declared "saints," that is, holy people worthy of respect and emulation. So were the apostles and members of Jesus's family--like Mary and St. Joseph. Christians started to pray to them to ask them for help from their posts in heaven. Other holy men and women—bishops and leaders among them--also began to join that distinguished group. By the 11th century, the Vatican started to get involved in the process, mainly to ensure that no unworthy people were declared saints. That process has grown stricter over time.
So here is what you need to do to become a saint, with God's help of course. And get ready for a long haul, too. It takes the patience of a saint to become one.