Unfortunately, the first thing you have to do to become a saint is to die. That leaves a lot of us out of the running. The purpose of being dead before becoming a saint is an important one -- you have the benefit of being in heaven along with God, Jesus and the Holy Spirit.
Step 2: Servant of God
This is where the process of naming a saint gets put into motion. While it’s generally five years after a person dies before the process can begin, there have been some exceptions.
There are three things to look at if a person is to be considered for sainthood (canonization is the Church’s term). First, the person must be thought of as having “heroic virtue;” second, they must be thought of as being in heaven, and third, they must be recognized by the Catholic Church for the sake of the faithful still here on Earth.
This step generally begins when people petition the bishop of the diocese where the potential saint lived to begin an investigation into that person’s life. The bishop will interview people who knew the person, collect the person’s writings, etc., then will write a report to determine if the next step should be taken. If the report is favorable, the person gains the status of “Servant of God.”
Step 3: Venerable
If the person is deemed “Servant of God,” then the findings of the local bishop are sent to Rome to the Congregation of the Causes of Saints. The investigation into the life of the person will continue, with a positive outcome being the person is deemed a person of “heroic virtue.” As part of this process a person called a “devil’s advocate” raises questions and objections to the candidate’s sainthood to make sure all aspects of the person's life is examined. (That's where the term originated) The congregation will also investigate the circumstances of the person’s death if they were killed – determining if the person was killed for his or her faith. The person is known as "Venerable" if they pass this stage. According to the church, people may seek their intercession in prayer at this point.
Intercession is an important point in the process, and is what will move everything else along. To become canonized, miracles are required, and the miracles come for a petitioner praying to the person for help. The miracles must be documented and investigated. There must not be means other than divine intervention that could have caused the miracle.
Step 4: Blessed
If a person claims a miracle happened due to intercession by the person in heaven, and it is investigated, confirmed and approved by the pope, then the would-be saint's status is moved to "Blessed." This process is called beatification. A ceremony is held when a person is seen as "Blessed," usually in that person's home town or home country.
Step 5: Saint
After the four previous steps are completed, there’s just one more, but it’s a big one. A second miracle must be investigated and confirmed. Once that happens, the person may be named a Saint. If they are, they are assigned a feast day on which they will be celebrated. A Mass at the Vatican usually follows that.
The sitting pope has the option to shorten any part of the process – including waiving the requirement for one or both miracles and not waiting to start the process until the person has been dead for five years.
Click here to read about the two miracles attributed to Mother Teresa.
Sources: according to the Catholic Education Resource Center, How to Become a Saint For Dummies; Catholichawaii.org