Don't focus on the negatives. Don't mention the LSAT unless they ask. If you have to mention a negative, try to follow up with a positive. "Yes, my LSAT score is lower than your 25% level but..."
DO focus on what you bring to the equation...relevant experience, maturity, committment to the education and beyond, etc., etc.
Most of this is off the top of my head, since I've only done job interviewing...but I'd treat it like that. Focus on why you're a worthy candidate and how they need you.