Get your birth date, exact birth time, and place of birth
Create your Vedic birth chart
Check whether Mars is placed in the 1st house
Check whether Mars is placed in the 2nd house
Check whether Mars is placed in the 4th house
Check whether Mars is placed in the 7th house
Check whether Mars is placed in the 8th house
Check whether Mars is placed in the 12th house
If Mars is in any of these houses, you are generally considered Manglik
Check the chart from the Moon sign as well
Check the chart from the Venus sign as well
See whether any Manglik dosha cancellation rules apply
Confirm the result with a qualified astrologer