If you want to become a spiritual master, begin with service to others.
Physical help, kind words and healing thoughts and prayers are ways to be of service to your fellow humans.
There is a famous Buddhist quote: Before enlightenment, chop wood, carry water. After enlightenment, chop wood carry water.
Spiritual growth is not dependent on a title. A small child with a pure heart and a desire to do good is as much a master as one who has studied and taken expensive “mastery” courses.
How do you know when you have achieved mastery? When you no longer care about being a “master,” it will simply be your way of life.