It might depend on what stage you fail at?
As for stage 2, exam 1 (written) and exam 2 (FEAST) are straight forward: read the information booklet for the former, and not much you can do to prep for the latter.
I got to the end and failed exam 3 (DART), and I can give one piece of advice for this one: don't just look at what's going on screen at present; plan ahead.