Don’t take it personally when someone turns you down. Assume they are like you: busy, occupied, distracted. Try again later. It’s amazing how often a second try works.
Everyone is shy. Other people are waiting for you to introduce yourself to them, they are waiting for you to send them an email, they are waiting for you to ask them on a date. Go ahead.
Rule of 3 in conversation. To get to the real reason, ask a person to go deeper than what they just said. Then again, and once more. The third time’s answer is close to the truth.