Here are few statements I have found. Few of them contains "GUIDELINES" and I strongly recommend you to go through the guidelines first. Trust me it will help. for example
"Do not expect your first SP draft to be perfect. Keep writing, put it away for a few days, and edit later"
If you follow the guidelines, you will be able to write a really amazing and impressive purpose.
--This is guidelines not sample
This is guidelines not sample
If you search "statement of purpose pdf" , "statement of purpose accounting" you will find many more samples and guidelines other than I have provided.
Good Luck and My Best Wishes.