Bring designers and developers together from the start
Accessibility decisions should be made before designs are treated as fixed. Developers can help designers assess what is practical to implement, identify technical constraints and suggest approaches that work across devices and input methods. This includes choices that may appear small, such as text contrast, as well as the behaviour of interactions for mouse, touch and keyboard users.
The collaboration should continue after design approval. Designers need visibility of implementation so they can confirm that the intended experience has been carried through, while developers can explain how technical choices affect usability. Treating inclusion as a late checklist creates pressure when deadlines are already tight. A shared process makes accessibility part of design, development and execution rather than a retrofit.
Sources: Designing and developing web experiences for everyone, No creator is an island