One of the most important techniques a good salesperson needs to develop is how to ask good questions, and then to ask them in the correct sequence.
Timing is everything.
This shouldn't be the first words out of a car salesman's mouth when meeting the prospect for the first time. Good question, wrong timing. There is a questioning technique called commitment and consistency which has to do with the sequence of asking questions. Once they go on record, they will be consistent with all their answers and will be reluctant to go back on anything they have told you earlier. Thus, you can get better quality answers to the questions to ask.