For our Spring Recruitment Drive at Drake University, we separated the event into three one-hour shifts with two people each from 2-5 PM on a Thursday. We didn't have a topic that we were standing up for, we were just hoping to find some libertarians and centrists specifically to check out the table. We had very few people walk by because unfortunately the school gives clubs a bad spot from which to recruit. Despite this, we were able to get three people sign up for YAL. (Two libertarians, one centrist)
On another note, you really need to be active in getting people to talk to you. You need to ask people specifically after loudly greeting them if they want to learn about YAL if you hope to recruit anyone. The only other memorable moment was a debate over the 2008 financial crisis with a well-educated liberal.