You'll be great at this because you should listen more than you talk and it's not a group thing. Just practice your hello with friends before-hand.
For the love of God, shut up. Listen 2.5 times more than you talk.
Ask for exactly the amount of time you intend to take. Ideally 15 minutes unless person suggests more. Ask them what's close to them. Make it easy for them to come talk to you. Be honest and forthright.