They ask about price or payment. They request you to demonstrate usage again. Non-verbal clues include the customer actually paying attention. Never ask whether the prospect wants the product or if the service will satisfy his or her needs. Instead, ask which alternatives of the product or service will more satisfy their needs.
Great salespeople are masters at presentation.
When the client understands what's in it for them, closing the sale becomes a natural conclusion to a mutually beneficial business relationship. If you ask enough questions you will eventually know when to go for the final close. The more you know about a prospect, the closer you are to closing. You get the information you need through your questions, through listening and during presentation of your product. Yet, like any achievement, it's often those extra steps that make the difference between success and failure.