In a mere four minutes, this interactive page imparts some of the most basic rules of good web design. Even if you’re not a web designer, it’s a great investment in 21st century literacy.
As someone who often dabbles in building websites, I always feel a bit uncertain about how to optimize my designs. This tutorial starts with the simplest possible web page and incrementally improves the readability, structure, and aesthetics in just a few simple steps.
If you’d like to go deeper, another great resource I recently found and loved is this online book: Refactoring UI. The link points to one featured article from this work, but I highly recommend the whole book.