Explicitly assign the responsibilities of the system to appropriate modules.
In a web context, an application is made up of layers, each being closer to the end-user:
Domain (farthest from the user)
UI (closest to the user)
The crucial rule in this context is the arrow of dependency. It states that a layer can never import or mention anything from another closer to the user.
This approach is a powerful concept and the key to a maintainable and scalable codebase.
My advice: never compromise on architecture. It's fine to be pragmatic and take shortcuts in any other areas. But you need a solid foundation for your system to grow and scale. It's virtually impossible to retro-fit this later.
Implementing a clean architecture is the same effort as implementing a convoluted one. It's a habit that is easy to pick up. See an example of these concepts here.
The layers are represented as modules in the workspace.
Architecture is not the same as folder structure.