Dependency Inversion Principle

high level modules should not depend on low level modules; both should depend on abstractions.

Test models thoroughly, test everything else less

Model all state in an application

Create a structured representation of the system's state

Ensure UI components can be loaded separately from an application

Single-Responsibility Principle

Every module, class or function in a computer program should have responsibility over a single part of that program's functionality, and it should encapsulate that part

Code an off-switch

Always plan for a way to switch your work off

Open–closed principle

Software entities should be open for extension, but closed for modification.

Documentation should be close to the code

Documentation, in all forms, should be as close as it can be to the code.

Compute properties when possible

One single source of truth

Data should be held in one location, duplicates of that data should be by reference only.