Working at top Hollywood talent Agency WME (William Morris Endeavor), I read countless scripts of varying levels of quality. But it was always easy to spot the screenplays that came from the rookies...
This should be obvious. But sadly it's still an issue in many scripts. But if you're planning to submit your script for critical review, please make sure it isn't riddled with mistakes. It's unprofessional and readers will understandably doubt your writing ability.
Solution: Carefully review your script for errors after taking a break from it for a least 3 days so you'll have fresh eyes. Or alternatively hire a copyeditor.
4. Muddled Motivation
A clear story and problem or goal motivating and driving the action forward is essential. All too often I received scripts to analyze and review from newbie writers, and even by page 20 of the script the actual point of the story wasn't clear. When you look at some of the most successful and top-grossing movies of all time: Titanic, Star Wars, Avatar...they all had clear motivations moving the stories forward.
Solution: Structure your story so that ideally within the first 10-15 pages you have introduced the general issue or goal driving your characters.
3. Unlikeable Characters
It's shocking how often this comes up. But there needs to be at least 1 primary character that audiences can empathize with or at least like. Even if your main character is a serial killer (I'm thinking of Dexter right now) you have to find a way to make that character likeable. It's essential to have a character that audiences connect to. Don't assume people will like your characters, just because you do. Did you watch The Circle? I read the book, and initially wondered why the movie didn't do better at the box office. After watching the movie, my questions were answered. None of the characters we remotely engaging and likeable. Note, I'm not referring to the acting. I'm talking about the writing. There was nothing in the screenplay to endear the characters to the audience or to help them relate to the characters. Don't make that mistake..
Solution: Create a situation that reveals something about the character or noteworthy attribute of your primary protagonist.
2. Try Too Hard To Be Different
You don't have to try to reinvent the wheel here. Sometimes really new writers want to try and prove themselves by crafting a really out-of-the-box story, told in a really unconventional way. Perhaps you want to break all the rules traditional scripts follow... Here's the thing...that can occasionally work. But you also have to know it's going to be a tough sell. Studios and agents like stories and structures that are familiar. And so do audiences. You might feel a really strong drive to be unique. Well that's a great thing. More unique and diverse voices are desperately needed in Hollywood. But that doesn't mean you can't apply your creativity and unique voice to an established template. It's all about execution. Tell a compelling story. Tell an untold or underrepresented story if you so desire. But tell it in a way that people can follow.
Solution: Familarize yourself with the typical formats Hollywood scripts generally follow. And if you deviate from that blueprint make sure you have a good reason for doing it and that you aren't just doing it as a gimmick to be unique. (I'll put a link at the bottom to an iconic screenwriting manual)
1. Thinking Quality Writing is Enough
Sadly in Hollywood talent and good writing skills aren't enough. Even if you've written the perfect script, that you're certain could be the next huge box office hit, you still need to get your script in the hands of the right people. In Hollywood it's all about who you know. Or more accurately, it's about who knows you! And unless you meet the right people, and make the right friends, your chances of selling a script are basically zero.
Solution: Network. Attend networking events & join industry groups where you can meet others in the industry. Also you can try and produce your film independently. If you're in Los Angeles, finding other aspiring film makers and actors isn't very difficult. So if you're resourseful and determined, you can bypass the traditional big studio route and still get your film made.
New to screenwriting and looking for guidance?
This is one of the best books I read on the subject. It's a classic and a must-read for any new writer looking to hone their craft.