Once you start picking up signals that it may be time to close, you can ask a “confirmation question” such as “How soon do you need this?”

If the customer gives you a date, you can proceed with the closing. If the customer still has objections or questions, you will have to handle those first.
This process of asking a confirmation question is sometimes called a “trial close.”
The benefit of a confirmation question is that it is something of a “closed question”. That is to say that it does not allow for the possibility that someone will come back and say “actually, I don’t think I want it”. If the customer is minded to buy the product, then they will already have been eased along the path to purchasing it by a simple question.
Rather than asking “So, would you like me to package this up for you?” the confirmation question allows you to garner that information without having to put the customer in a position where they answer a “Yes/No” question.
At this point, it is more than likely that the customer’s verbal and non-verbal signals will already have given a big lead as to their intentions. If they are making statements which pertain to where in their house the product would fit, or how they would use the service, then they are clearly already picturing themselves with the item, and they are as likely as they ever will be to be receptive to an attempt at closing.
The nature of your closing technique is important here, but the main thing to remember is that as long as you are respectful to any concerns they may have, you are all but guaranteed the sale.