Start with the four accessibility principles
WCAG organises accessibility around four principles: content should be perceivable, operable, understandable and robust.
Those principles are useful because they keep accessibility broader than a checklist. They ask whether people can get the information, use the interface, understand what is happening and rely on compatible markup.
Keyboard access is a simple test with high value
Interactive elements should be reachable and usable without a mouse. Focus should be visible, tab order should make sense and controls should not trap the user.
Keyboard testing often exposes interface problems that also affect power users and people navigating on unusual devices.
Content needs alternatives and structure
Meaningful images need appropriate alternative text. Videos may need captions or transcripts. Headings should form a logical structure rather than being chosen only for visual size.
Clear labels and instructions also matter, especially in forms where errors need to be understandable.
Visual accessibility is more than colour contrast
Contrast is important, but so are text size, line spacing, zoom behaviour, motion and whether information is conveyed only through colour.
Interfaces should also respect reduced-motion preferences where animation is not essential.
Automated tests are useful, but incomplete
Automated tools can catch missing labels, contrast issues and some structural problems, but they cannot determine whether an experience is genuinely understandable or practical to use.
Manual keyboard testing, zoom testing and, where appropriate, assistive-technology testing should complement automated checks.
WCAG is a technical accessibility standard, not itself a law. Legal obligations depend on the organisation, service and jurisdiction, so businesses should avoid treating a plugin score as proof of legal compliance.
What to do next
If one of these issues is affecting your current website, the useful next step is not automatically a full rebuild. Start by identifying whether the problem is structure, content, design, performance, maintenance or a combination of them. That makes it much easier to decide whether to improve the existing site or redesign it properly.