Suggest a few things. That's apparently very popular. Confuse people at the point of purchase. From everything I've read, you need to make this part of the business Web site conservative and extremely easy to follow. Get it all on one page if you can.
People are still very nervous about putting credit card numbers into their computer.
Make it so they feel safe. If they have to go from page to page then maybe you're asking too much. Another site said to only ask for information that is required. If you start asking people's age, height, income level, and the like, they can get nervous and maybe crash the sale. Fail to acknowledge the sale.