Greg Koukl is a Christian apologist, radio talk show host, author, and speaker. He is the founder of Stand To Reason, a Christian apologetics and training ministry. Koukl’s book Tactics is a must-read for any Christian interested in sharing their faith (which should be each of us).
When you're in a stressful conversation of any kind - but especially about religious ideas - asking questions is a key strategy. Rather than working to have all of the answers (which isn't bad), it may be as helpful to learn to ask good questions.