"You’ll most likely be told to write what you know from dozens of screenwriting books, screenwriting professors, seminars, fellow students, and probably even strangers while preparing to write a screenplay, but if there’s one thing I’ve learned as a story analyst in Hollywood, it’s this:
If we all wrote what we knew on a first hand physical experience level, we’d be bored out of our minds!
Before we go any further, let’s just say that there are two ways you can look at the phrase “write what you know”:
1. Set out to write about your physical experiences and observations in life as an individual.
2. Set out to write about your thematic experiences and observations in life as an individual.
So which is it?
If you picked the first, consider yourself aging at an incredibly rapid speed until there’s nothing left but a dusty old pile of bones. If you picked the second, and I think we can expect a quote from The Last Crusade here, “You’ve chosen … wisely.”
If you’re thinking about arguing this point … just … don’t. I’ve read far too many screenplays based on the first example to give you the time of day. Simply put, the phrase “write what you know” is a misinterpreted phrase. More often than not, many people will encourage you to write all about your summer at camp, your first year in college, the non-adventures you and your friends share, but the fact of the matter is that there’s more to it than that.
It’s all about theme."