Accessibility isn’t really about the points you’re describing. The things you’re mentioning would be helpful, but really they’re just general usability points. 

Yes, it’s a subset of usability, but that subset is disability. Much of  the work is enabling compatibility with assistive tech through things like proper labelling, and much of the rest of the work is ensuring that you aren’t disadvantaging or excluding disabled groups by including any unnecessary barriers.

One of these unnecessary barriers is relying on colour to convey information, doing that is a sure-fire way to annoy or exclude many (10% of white males are colour-blind) of your users.

Colour should only ever be used as a supplementary means of re-enforcing information. For example your recommendation to use blue to indicate links isn’t much use if you don’t know what blue is (tritanopia) so it should be used just to re-enforce the primary means of conveying that information, for example an underline on the link.

Another good example – use of the colour red to indicate form fields with errors should just be a re-enforcement of the primary means of conveying it, ie. text and a cross icon.

That may of course be what you meant to say anyway, but it isn’t the message that comes across in the text.

Google image search annoyed me most recently. I have a 1280×800 pixel mobile device, Google detects that I have a mobile device and presents horribly low resolution versions of the original images. I tried Dolphin HD and set it to desktop mode, but it appears that Dolphin HD is not compatible with the JavaScript that Google uses for their page load…would have been happier with the old page based desktop version!