In order to make eLearning content accessible and usable you should:
- ensure materials are simple, clear and well structured
- provide appropriate text equivalents for images, graphs and charts
- ensure that content provided as rich media is available for everyone to use and engage with, including those with disabilities
- ensure that colour is not the sole method of conveying or distinguishing between visual elements and that sufficient contrast exists between foreground and background elements
- ensure tables make sense and identify headers for data tables
- identify document language and any changes of the language
- adopt a systematic approach to check for usability and accessibility
For a more comprehensive set of guidelines developers could consults WCAG 2.0.