There are a few things that you may want to avoid when writing a screenplay:
Lack of structure: It's important to follow the proper format and structure for a screenplay. Avoid deviating from this structure or making the screenplay too hard to follow.
Poor character development: Make sure that your characters are well-rounded and believable. Avoid using one-dimensional characters or characters that are too perfect or flawless.
Too much dialogue: While dialogue is an important part of a screenplay, be careful not to rely on it too much. Avoid having long stretches of dialogue without any action or visual elements to break them up.
Lack of conflict: Conflict is essential to any good story. Avoid using too little conflict or using conflict that is not believable or well-developed.
Lack of visual elements: A screenplay is meant to be a blueprint for a film, so it's important to include plenty of visual elements. Avoid writing a screenplay that is too dialogue-heavy and lacks description of setting and action.
Overall, the key is to create a compelling and well-structured screenplay that will be easy to understand and enjoyable to read. By avoiding these common pitfalls, you can create a strong foundation for a successful film.