People don’t know what to do when they first come in, and they are uncomfortable doing nothing. Give them something to do–eat. Give them something to eat. Eating relaxes people and puts them at ease. It gives them something to do and relieves the awkwardness.
Providing refreshments each week is easy enough to do. First, someone needs to be in charge. Not in charge of making refreshments every week, but in charge of seeing that it is taken care of. About every two months, they can pass around a sign up list with dates for people to volunteer. If it is a large class, you may need several to volunteer each week. A friendly e-mail reminder to the people who have signed up each week would go a long way toward insuring that it is done.
From Good Questions Have Small Groups Talking: the book.