Those reading this thread for genuine hints and tips, I hope you can filter the good stuff from the bitter musings (whatever their motivations).
Remember not everyone can be successful, there is an element of competitiveness in it and BA are looking for so much more than just 'driver airframe'. You will need to be technically competent but the non technical stuff is just as important. You are being recruited as a 'Captain of the future' where full role reversal happens from day one of your career.
There are some genuine tough luck stories out there, the recruiting procedure can't be completely foolproof, after all fools are so inventive! However the correct preparation seasoned with a sprinkling of luck will give you the best chance.
Good luck all.
ps. All the above is just my personal opinion.