The <table> element is for data that one might find in a spreadsheet, consisting of rows and columns of cells. Browsers provide this mechanism to display table structures and to convey table data to assistive technologies. It's important to ensure that the editing process allows identifying row and column headers so that screen reader users can access the meaning of each data cell by understanding what row and column it appears in.
Lists are collections of related content. For example, a navigation bar is a list of links or a set of instructions may be an ordered (numbered) list. Clearly identifying a set of items as a list helps people understand that relationship. When you include a list in your page content, this relationship needs to be conveyed visually, and it also needs to be conveyed to people using screen readers.... Read more about ✎ Technique: Identifying lists of content
Headings are important orientation aids, and they help people quickly identify the content on your page. When headings are correctly identified, they also allow screen-reader users to quickly navigate from heading to heading using the screen reader's heading navigation functionality.
The best way to do this is to ensure that headings are identified in HTML. When using a web-content editor or a word-processing application, you can do this by making use of the heading options in the styles menu. ...
The heading levels (1-6) are often considered a way of describing and determining the “importance” of a heading, with h1 being the most important. This might be reflected in the visual appearance of headings—higher-level headings typically appear as bigger and bolder text than lower-level headings.
But you can't just put an “important” heading anywhere. Its heading level relates to how much content it refers to, and that has to do with structure.
Reflecting structure accurately allows screen-reader users to use their screen reader's heading-navigation feature to navigate by heading level, building up an idea of document structure. It also ensures that, for people who use custom stylesheets, heading structure is preserved even when the appearance of headings is changed.... Read more about ✎ Technique: Heading structure