Get a copy of RANT, and practice, practice, practice!
Another way of looking at it, though: surely your school shouldn't put you forward for any kind of check or test unless they think you're ready? Which leaves one of two options.
Either your school is being less than competent by putting you forward for the check too early, in which case have a chat with your instructor, and if you can't delay the test until you're happy then find another, more understanding, school.
The other option is that your instructors believe that you are at an appropriate standard to be able to do this stage check, and you are setting yourself standards which are too high for your experience.
FFF
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