well~ personally I feel nervous talking to any stranger, especially if they are native English speakers. It’s because Im not confident in my English. Im afraid of making mistakes that may make me look like a fool. I tend to speak quietly but when people ask me to repeat or when they dont understand me, I feel bad and lose even more confidence. Sometimes my head is just blank, I dont know how to keep a conversation going so I think people lose interest in talking to me. With those negative thoughts in mind, It is always hard for me to start to talk to people.
I think first expression is extremely important. In the first meeting if tutors can show that they are friendly, helpful and sympathy that would be good. Also encourage students to speak freely and loudly or ask suggestive questions to keep the conversation going. I found its usually hard to focus for more than 20 min so change activities every 20 min would help too.