The best way to get "The Call" is to:
1) Make sure every single line/question is completed for the application (even things you think are trivial ie repeating the same fax number)
2) Have a current employee (preferably a pilot) personally see the head of hiring to have him/her pull your app.

I didn't get the call initially either, all though my info was in and current the same time my buddies that got hired into the first class and second classes.

Be persistent....I had a buddy walk in and he was told I would be sent an invitation. I patiently waited for that email and it never came. Another friend walked in months later and requested the same thing. When he pulled my application he said I had already been sent an invitation to interview and were awaiting my reply!! My buddy politely but persistently convinced him to re send the invitation for an interview, and watched him hit the send key on the computer. Guess what.....after a week (not including the first 4 months of waiting) I still hadn't gotten the email to interview.....
Long story short.......PERSISTENCE