One way to start is with reading the right books. Two good examples are How to Think Like a Millionaire and The Millionaire Next Door. Once one digests the information inside, the millionaire mindset becomes apparent. In particular, there are five things that stood out for me:
1. Passionate to succeed in life's goals - If you want to be successful in anything, passion is a requirement. If you don't have that passion, achieving your goals is going to be like climbing