Make sure all images have an alt text. (click on the image, then click the 3 vertical dots to add alt text). Note: images inside a Google Slide should also have an alt text. In Google Slide right-click on the image to add alt text.
Make sure to use headings for page headings so that they are logically oriented and parallel. Do not use heading labels for normal paragraph text.
Do not use text like "click here", "more information," or "details" for hyperlinks. The hyperlink test should be meaningful.
Example Course Outline rather than click here to access the course outline.
Make sure posted documents are accessible. Simple Guide to Creating Accessible Documents for the Web
Avoid center-aligning large amounts of paragraph text.