The Dr. Jekyll & Mrs. Hyde blog had a quite good post on writing personal statements.
There’s a tricky thing about personal statements: It’s almost impossible to find good and bad examples of them. Because personal statements are part of competitive applications for programs or positions, they’re confidential, and rightfully so. It’s almost impossible to see how other people do them.
Thus, people don’t have an easy way to learn that something that is highly important to them personally – like having seen a close relative struggle with illness – is not that unusual. It’s easy for a professor or administrator to joke about the “grandmother story” being a cliché, but someone trying to write a personal statement for the first time has no easy way of knowing that their story is common.
The moral, for someone trying to write a personal statement, is to find someone who reads them regularly and get feedback before you send it off to that big program you’re interested in.