E.B. White wrote that there are “no inflexible rules by which the young writer may steer his course. He will often find himself steering by stars that are disturbingly in motion.” With this in mind, we’ve asked working screenwriters to share a list of the “un-rules” that they find most helpful in their writing careers.

Our latest list of “un-rules” comes from the always insightful Billy Mernit. Billy writes Living the Romantic Comedy, a great site that anyone writing romantic comedies or comedies in general should treat like gospel. Known as “the guru of rom-com” for his best-selling screenwriting textbook, Writing the Romantic Comedy, Billy teaches at the UCLA Extension Writers’ Program and contributed two chapters to the recently published Cut to the Chase: Writing Feature Films with the Pros at UCLA Extension Writers’ Program.

Billy published his first novel Imagine Me and You in 2008. During his many years in the entertainment industry, he has written for television and worked as both a screenwriter and private script consultant. After being a story analyst for Sony and Paramount, he has held that job at Universal Pictures for the past fifteen years. At Universal, he’s had a hand in the development of such recent successes as Bridesmaids and Pitch Perfect.

Billy chose to approach his rules from the perspective of a story analyst. Here are his top three truisms:

A primary goal of any spec script that’s going to market is to get the reader to identify with its protagonist. Your story requires a compelling, relatable lead character – meaning, we know what she wants and we believe she may be capable of getting it, the ways in which she overcomes her obstacles make her empathetic, and she’s complex enough to keep us interested. Your job is to get us to be her, even if this means putting what she thinks and how she feels into the narrative on the screenplay page. If we’re not totally emotionally invested in her story and seeing it though her eyes by the end of the first act, your script is dead in the water. No amount of great writing can overcome the folly of a weak story concept. It’s an awful truth, but it’s undeniable: While I’ve often seen an exquisitely crafted screenplay be rejected by a studio, I’ve never heard of one with a great story idea being turned down due to its poor execution. In this business, story concept rules, so no amount of skillful tap-dancing (e.g. pithy dialogue, cool visuals) can make up for the lack of a killer melody (i.e. a genuinely exciting same-but-different premise). Unless your script’s stripped-naked story idea earns an aroused “And then what?!” response when it’s pitched, you’d be ill-advised to spend the next few years of your writing life working on it. Learning the difference between what a writer likes and what the audience wants is vital in forging a successful career. Screenwriters may write to express themselves, to capture a personal experience, or to make a philosophical point, but an audience wants to be entertained and moved, and their demands trump yours. You have to develop a keen sense of what appeals to you as a viewer in a story, so that you can step back from your own work with objectivity, and be ruthless about losing whatever’s in the way of holding an audience’s attention or satisfying their expectations. Such hoary mantras as “Come in late, leave early” and “Kill your darlings” speak to the ethos of this rule: a screenplay is a shark that has to move to keep breathing, and lives on conflict. So always keep your ego at the service of feeding that beast.

Remember to check out Billy’s website Living the Romantic Comedy for more screenwriting insights.