Write your code so that it reflects, or rises above, the best parts of your personal character.
Strive for beauty and elegance in every aspect of your work.
Value clarity equally with correctness. Utilize the proven techniques that will produce clarity in your code. Correctness will likely follow suit.
Use the visual layout of your code to communicate the structure of your code to human readers.
Always favor the explicit over the implicit.
The most reliable document of software is the code itself. In many cases, the code is the only documentation. Therefore, strive to make your code self-documenting, and where you can't, add comments.
Comment in full sentences in order to summarize and communicate intent.
Take reasonable steps to test, document, and otherwise draw attention to the assumptions made in every module and routine.
Never make the user feel stupid.
The time to write good code is at the time you are writing it.
A true professional does not waste the time and money of other people by delivering poor quality work.
Note: this version of Principled Programming is the "short form." A longer version is also available which includes commentary and explanation with each of the principles.