When you’re stumped as to how to begin a piece of writing, consider doing one of the following:

• Simply tell the reader what the subject is.
• Make a blunt statement.
• Cite a statistic.
• Tell a first-person anecdote that’s relevant to the subject.
• Tell a third-person anecdote.
• Put up a straw man, then knock it down.
• Summarize a current state of affairs (or the conventional wisdom), then tell what’s changed.
• Summarize previous research, then tell what new research has found.
• Involve the reader in a bit of conjecture.
• Start with a quotation from a famous figure. (But beware of triteness.)
• Commit an egregious exaggeration. Then explain what the (less extreme) reality is.

Link: How to Write an Opening Sentence via asserttrue.blogspot.ca