How do you win them over? Just be yourself.
Usually during OVs you are not “quizzed” about anything in particular. Usually the main purpose (for the school) is to get a sense that personalities are compatible, and that you are sincere in your interest to attend the school and be a team member. Your purpose, similarly, should be to confirm your current strong feeling that you would be comfortable with the team and school.
If you have a positive academic pre-read, and the coach has decided to spend the money and commit his/her time–and the time of your prospective teammates–to give you an OV, you can be very confident that your academic credentials have been considered adequate for admission as a athletic recruit.