I've just been shortlisted for a GD(P) bursary, and was turned down last year for a sixth form scholarship. However, both times I passed the interview. Before you attend OASC you get given a really useful book - the blue one. There is a table towards the rear showing you the qualities needed by all candidates, I just memorised them each time, and in both interviews read off the qualities that are needed by commissioned officers.
By the way, on your first application, did you get a shot at part two? Because if, on your next application, you make it through, you need to have prepared for it. Try not to focus 100% on the interview, although you must obviously pass it.
Breadth of interest is what they are looking for, and it seems to me that this is the area where you may need to improve.
Good Luck!
TMA
p.s. what were you actually applying for? DE or Bursary?