An 'A'script has the following features:
1 accurate language - few slips only, no serious errors like errors in tenses
2 accurate spelling across the board
3 precise vocabulary - do not be too obsessed with idioms and flowery phrases. many students use bombastic words but it is not suitable.
4 interesting and original...write from the heart
5 correct tone - if it is formal, then use a formal tone, if it is a friendly letter, then it should sound informal...
Jun, go ahead and write your imaginative essays but be careful about your errors. Do not write too long. Leave about 10 minutes for editing.