Hi! I currently go to Lawrenceville! If they offered to give you another interview and you would. be able to do it I would say go for it! Interviews are the best way for the school to get to know you and you to get to know the school a little more 
I would say just continue what you are doing, focus on your grades and scores. However, your grades and scores are not the most important thing because just like with college admissions, your grades are not what will get you in at the end it will be you extracurriculars, your essays, and your interview!
Good luck!! If you have any questions about Lawrenceville I am a rising junior there so I would be happy to answer any!