Hi, a lot of the time it is about getting your foot in the door and getting contacts especially in academia. I hate to say it and it is such a cliché but that is how it seems to work! A lot of the time they seem to have someone in mind for the job and are just interviewing because they have to. That is not always the case but this maybe the case at more prestigious unis that everybody applies to. Having said that, all is not lost as references are a key point - make sure you've got the best refs possible. They could be the key in giving you that edge! Is there any possibility that you can do any volunteer work in the area you want to move into as that always goes down well especially as you are going into a very competitive field. As for interviews I can sympathise with you there but I think preparation is vital. I think if you show that you’ve done the background reading that's a good start and ask questions even if it's just about the library resources. Good Luck, stick at and believe in yourself!!!