In the intro you should say who the statement might be said by. For example if it was: 'If God is all loving, why is there evil in the world?', you could say 'This statement could have been said by an atheist.' Then say what is challenges e,g. 'This may challenge a Christian who believes God loves everyone equally.' To make it a really solid A* essay, you could end in a question: 'So, if God is really omnibenelovent, why does evil exist?'
Then go onto your main body/conclusion! Good luck for tomorrow!
I tend to start of by immediately stating whether I agree or not, then provide two reasons why i disagree then challenge those reasons with agreed reasons. Then the conclusion chooses the best reasons and why i chose them.
It's probably too late reply. However if/when you have the next R.S exam (i.e. Medical Ethics, Religion & Equality e.t.c.), I find like shaan says to start off with your GUT reaction (what's your opinion) and explain it.
From there, you provide one side of the arguement and explain their reasons why they oppose or agree with the statement.
I tend to begin with "Critically speaking, [statement]". E.g. Critically speaking, the teleological argument is not convincing. While, [argument for it being convincing], scholar [name] argues that [statement] which makes the argument significantly less convincing as we can observe [way we see this in everyday life/ through experience etc.]"