The Create Performance Task is where most AP CS Principles students either pull ahead or fall behind, because it isn't graded on how impressive the program looks. It's graded on whether your written responses clearly explain what the program does and why you built it the way you did.
Pick a program you can explain simply. A program with one clear purpose and a manageable number of features almost always scores better than an ambitious one you can't fully document. Judges are reading your written responses closely, and vague explanations of a complex program score worse than clear explanations of a simple one.
Identify your list early, and use it meaningfully. The task requires a list (or comparable data structure) that plays a role in your program's logic, not one that's just declared and ignored. Decide what the list stores and how the program uses it before you start building.
Document your procedure with a parameter that changes behavior. You need a student-developed procedure that has at least one parameter, and that parameter needs to meaningfully affect what the procedure does. This is one of the most commonly under-explained parts of the task.
Write the responses as you build, not after. The video and written responses ask you to explain algorithms, abstraction, and data use in your own words. If you wait until the program is finished, you'll spend hours trying to reconstruct decisions you've already forgotten the reasoning behind.
Keep the video under the time limit and focused. It only needs to demonstrate the program running and the input/output behavior you're describing. It doesn't need production values.
Students who succeed here treat the written component as equal in importance to the code, not as paperwork to finish afterward.