to be honest, i don't think 'cramming sessions' do much good.
that's my opinion however.
my attitude towards exams are:
"i've learnt all that i could have learnt, in the time that i had been given"
because when you think about it, cramming for the last 5 minutes prior to an exam, i don't think you'll be able to memorise a great deal (if truth be known, i have done this on many occassions in the past but to no avail).
it is also true that you cannot 'push information out of your brain' as such, but what you will find is you will try to memorise 'new' information in the last 5-10 minutes before an exam is due, rather than focusing on your strengths, ask yourself:
what do i know?
how can i explain, what i know?
it depends on the subject,
but once you start writing one word down, you can create a mindmap (brainstorm) with various other areas that you had thought you'd forgotten (i hope that made sense
).
on a personal note,
i've always studied until midnight,
had five to six hours rest,
got an early start (say 5am to 6:45am studying, when your brain is at it's freshest), and having breakfast (NEVER forget/skip breakfast, it's the most important meal of the day!!!)
you'll feel confident walking into an exam,
but don't become arrogant or cocky
(i'm guilty of this ... it's in my nature *at times*)
but what you must remember is,
you've learnt all you could, focus on your strengths, if you're worried about not-knowing things, try to fudge it (although i don't recommend this, at least you will get more marks writing a couple of sentences or lines gaining 1 or 2 'initial' marks as opposed to a zero mark for that question).
i hope this helps