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Solid Start
Getting started (again) with web accessibility does not need to be hard. The author has done such a great job in explaining the fundmentals of web accessibility.
Understanding Accessibility
Although this website is for web designers, I find it useful for web developers too. People always want more. Why won't a web developer also become a great web designer?
The 7 Principles - Centre for Excellence in Universal Design
There are many people who write about good principles for great design. But this one can be applied to web design too.