I applied once years ago and heard back straight away but after a little pprune research found out about the one month trial thing and at that time wasn't prepared to give up my job for a maybe. So I politely cancelled my interview with plenty of notice.
I applied this time around and heard NOTHING.
A girl I know was invited for an interview,she has very little commercial experience and no private. And, with out sounding too b****y it certainly wasn't a looks thing!
I have found with this kind of aviation they want what they want and you can't make yourself crazy trying to work out what that is.
I recently applied for another job along with a friend who has similar experience to me and I got an interview and she didn't. When I went to the interview I was VERY surprised that she didn't when I saw the standard of some of the girls there.
All you can do it apply for as many jobs as possible and hope for the best!