St. Monica (August 27) is the mother of St. Augustine (August 28), though Augustine was no saint when Monica began her earnest intercession. At that time he was a pagan and a member of the heretical Manichean sect. He was known to be a carouser who lived with a woman to whom he had fathered a child. A brilliant mind, he was "devoted" to his views and his lifestyle, and had no intention of converting to the Catholic faith.
St. Monica was distraught about her son's dissolute ways and decided to do something about it. She prayed. And in the end, her prayers won the soul of her son.
What was it that made St. Monica's prayers so effective? I think five strategies are primarily responsible. Perhaps you can implement them as you seek to evangelize those you love.