french oral... help!

Try to use opinion fillers when you can't remember what to say. Memorise phrases like:
Je trouve que...
Je crois que...
Je dirais que... ("I would say that" this is conditional tense)
On peut dit que... ("One could say that")
And then always follow this with justification, using the words:
...parce que
...car
...puis que
Try to get in one opinion on each topic you discuss.

thank you so much! do you think 5 opinions would be okay?

That's definitely enough for a GCSE oral! "Je dirais que" is a good way to get the conditional tense in. Try a subjunctive too if you're aiming for A/A*. An easy one to remember is "Je ne pense pas que ce soit..." followed by something like necessaire or falloir ("I don't think that it is... e.g necessary")
You'll learn more about the subjunctive at AS if you carry on with French. 'soit' is just the subjunctive form of 'est' triggered by the use of "Je ne pense pas que"