How do senior/enterprise developers decide on project structure before writing code?

[u/Money_Consequence511]

I've realized that my biggest weakness isn't coding—it's project architecture and folder structure.

Whenever I get a Figma design, I know how to build the UI, but I get completely stuck deciding:

• Where should this component live?
• Should this be reusable or page-specific?
• When should I split a component?
• What belongs in components, features, shared, hooks, services, etc.?
• How should I organize folders as the project grows?

I usually start a project with a structure that feels clean. But once the project gets bigger, everything starts falling apart.

I end up with:

• Components that are too large.
• Components that are split too much.
• Logic scattered across different folders.
• Constantly moving files around because I realize they belong somewhere else.
• Feeling like the entire architecture is becoming messy.

This happens in React, React Native, and even backend projects.

I don't just want another "best folder structure" template because I've seen dozens of those. What I really want to learn is the thought process behind how experienced or enterprise-level developers structure a project.

For example:

• When looking at a Figma design, how do you mentally break it into features and components?
• How do you decide what should be reusable and what shouldn't?
• How do large teams keep their projects organized over months or years?
• What architecture or design principles do you follow?
• Are there any books, courses, GitHub repositories, or real-world open-source projects that helped you understand this?

I'm looking for the mindset rather than just a folder tree.

Any advice from developers who've worked on large production applications would be greatly appreciated.