I'm a firm believer that once you are in the door the day of the interview, it's an even slate for everyone. Chances are, if they called you in for an interview, you're qualified, so I would venture to say it's time for a different approach.
Airlines hire personality and perceived aptitude and motivation. My advise would be to study the Jepp legend, the AIM, Mental math for pilots, ALL gouges on aviationinterviews.com.....and I mean study...harder than for your hardest final in college.
Even more importantly is to get those online gouges and gouges from your friends and get an idea for what kind of HR questions they ask. Print out a list and start thinking about how you'd answer them....always put positive spin on a negative or loaded question....sit in front of the mirror and practice.
I've been to 5 interviews and have been offered 4 jobs. I crashed and burned at one and it was because i was ill prepared...I've also been in an interview (ACA) where a fellow interviewee crashed and burned hard. Don't ever lie (we've all broken FARs) and do your homework on the company.
I'm rambling, but keep studying....and study for their interview, some airlines ask entirely different types of things based on your experience. Most importantly, don't give up and always tell them that you really want to work there and become part of their team.
Good luck. Keep your head up.