Accessible forms start with persistent, visible labels rather than placeholders. A <label for="id"> paired with its input, or a label that wraps the input, provides an accessible name, increases the click target, and remains visible while users type. Placeholder text, by contrast, disappears as soon as the user begins typing and typically fails contrast requirements, so it should never be the only label. Required fields should be marked both visually and with aria-required="true" or the native required attribute, and validation should run on blur rather than on every keystroke to avoid interrupting users in the middle of typing.
Error handling must be specific and well connected. Each field with an error should set aria-invalid="true" and use aria-describedby to point at the inline error message so screen readers announce the error when the field receives focus. A form error summary at the top of the form, listing each problem and linking to the offending field, lets keyboard users jump directly to what needs fixing without hunting. Success messages after submission can be placed in an aria-live="polite" region so screen reader users hear the confirmation without losing their place. Additional helpers such as autocomplete attributes for common inputs and inputmode hints on mobile keyboards further reduce friction for everyone.
Images need alt text that conveys the purpose or content of the image rather than its appearance, and screen readers already announce the word "image," so phrases like "image of" should be avoided. Decorative images should use an empty alt attribute, alt="", so assistive technologies skip them entirely. Complex images such as charts benefit from a brief alt plus a longer description referenced through aria-describedby or visible nearby. SVGs can be made accessible with a <title> child for the accessible name, an optional <desc> for longer description, and role="img" on the <svg> element. Document structure is equally important: a logical heading hierarchy that descends from h1 through h2 and h3 lets screen reader users scan pages the way sighted users skim; descriptive page <title> tags announce the topic on load; the <html lang> attribute enables correct pronunciation; and passages in other languages can be marked with a lang attribute on the wrapping element. Descriptive link text should make sense out of context, and unique IDs across the document prevent references like aria-labelledby from confusing the accessibility tree.