Choose an Accessible Theme - when considering WordPress themes, choose themes that are tagged as accessible ready.
Perform Accessibility Checks on Themes Before Implementation - before selecting a theme not tagged as accessible ready, do some accessibility checks on theme demo sites or actual live sites using the theme with tools like the WAVE and Siteimprove browser extensions.
Check Plugin Accessibility Before Implementation - some WordPress plugins can introduce new accessibility issues not present in a theme, so all plugins should be tested for accessibility before implementation.
Make sure all documents are accessible - Before you post any documents to a WordPress site (PDF, Office files, etc.) be sure to check them for accessibility compliance by using built-in accessibility checkers and remediation tools. Visit the document accessibility page for more information.
All Images have Alternate Text Descriptions - All images posted to a website must have alternate text that is meaningful and descriptive. Be sure to check that all images have proper alt text and instruct site users how to stay in compliance after site launch.
Considering Installing the WP Accessibility Plugin