"If you design with a disabled person in mind, you’ll create a better product for everybody to use."

Write in plain English
Describe all images and videos with alternative text
Test with actual users https://link.medium.com/vux3P7k07W 

I'm obsessed with these concepts.

If we use our own abilities as a baseline, we make things that are easy for some people to use, but difficult for everyone else. — Microsoft inclusive toolkit

https://www.microsoft.com/design/ 

Write in plain English

http://www.hemingwayapp.com/ 

Use good colour contrast

https://snook.ca/technical/colour_contrast/colour.html#fg=33FF33,bg=333333

To check out whither or not your content is good for colour blindness, there are awesome apps out there:

Sim Daltonism
https://michelf.ca/projects/sim-daltonism/
Color Oracle
https://colororacle.org/ 
ColorBlindness SimulateCorrect
https://play.google.com/store/apps/details?id=com.SeewaldSolutions.ColorBlindnessSimulator

These are great resourcea to see how accessible your website/s are for blind and visually impaired individuals:

NonVisual Desktop Access (NVDA)
https://www.nvaccess.org/ 
VoiceOver
https://www.apple.com/ca/accessibility/mac/vision/
Job Access With Speech (JAWS)
http://www.freedomscientific.com/Products/software/JAWS/